unit 6: physical behavior of matter notes cw 6: physical behavior of matter notes & cw ... o the...

1

Unit 6: Physical Behavior of Matter Notes & CW

Unit Objectives:

Distinguish between the three phases of matter by identifying their different properties and representing themwith particle diagrams

Perform simple conversions between Celsius and Kelvin temperature scales Differentiate between exothermic and endothermic reactions/changes Identify phase changes, and understand how to read a heating or cooling curve Define heat, and understand how it varies from temperature Solve heat equations Solve Combined gas law problems State and understand the Kinetic Molecular Theory (KMT) Understand the relationship between temperature, volume, and pressure among gases using the following gas

laws: Charles’ Law, Boyle’s Law, Gay Lussac’s Law

Focus Questions for the Unit:

How does particle behavior determine the physical state of a sample of matter? How do attractions between particles affect the physical properties of solids, liquids, and gases? How do particles in the gas state respond to changes in conditions?

YOU SHOULD BE ABLE TO ANSWER THESE IN DETAIL BY THE END OF THE UNIT

Define the following vocabulary: Absolute Zero Kinetic EnergyAvogadro’s Law Kinetic Molecular Theory (KMT)Boiling Point (Normal) MatterCompound Melting

MixturePotential EnergySublimationTemperatureVapor Pressure

Cooling Curve DepositionEnergyElementEvaporationHeatHeat of FusionHeat of VaporizationHeating Curve

2

The bold, underlined words are important vocabulary words that you should be able to define and use properly in explanations. This is a study guide for what you will be tested on. The objectives are divided into categories of “Knowledge” (what you have to know) and “Application” (what you have to be able to do).

PHYSICAL BEHAVIOR OF MATTER

Knowledge Application

1.

o Physical properties of substances can be explained in terms ofchemical bonds and intermolecular forces.

o Intermolecular forces created by an unequal distribution ofcharge result in varying degrees of attraction betweenmolecules. Hydrogen bonding is an example of a strongintermolecular force that occurs in compounds containing Hbonded to F, O, or N atoms.

o Physical properties include malleability, solubility, hardness,melting/freezing point, and boiling point.

o Predict relative melting and boilingpoints of compounds giveninformation about its chemical bondsor strength of intermolecular forces

o Predict relative strength ofintermolecular forces of a compoundgiven its melting and boiling points

2.

o The three phases of matter (solids, liquids, and gases) havedifferent properties.

o The structure and arrangement of particles and theirinteractions determine the physical state (s, l, or g) of asubstance at a given temperature and pressure.

o Draw and interpret a particle diagramto differentiate among solids, liquids,and gases

o Explain phase change in terms of thechanges in energy and intermoleculardistances

3.

o Heat is a transfer of energy (thermal energy) from a body ofhigher temperature to a body of lower temperature. Heat(thermal energy) is associated with the random motion ofatoms and molecules.(Heat flows from HOT materials to COLD materials)

o Temperature is a measure of the average kinetic energy ofthe particles in a sample of matter. Temperature is NOTenergy – it is a measure of heat energy.

o Distinguish between heat energy andtemperature in terms of molecularmotion and amount of matter

o Convert between degrees Celsius anddegrees Kelvin (Table T)

4.

o The concepts of kinetic and potential energy can be used toexplain physical processes that include: fusion (melting),solidification (freezing), vaporization (boiling, evaporation),condensation, sublimation, and deposition.

o The kinetic and potential energy changes involved in thesephysical processes can be illustrated in a heating curve orcooling curve.

o Identify areas of heating and coolingcurves that show changes in kineticand potential energy, heat ofvaporization, heat of fusion, and phasechanges

o Calculate the heat involved in a phaseor temperature change of a sample ofmatter using Tables B & T and/or agiven heating or cooling curve

5. o Physical processes like phase changes can be exothermic or

endothermic.o Distinguish between endothermic and

exothermic phase changes

6. o Entropy is a measure of the randomness or disorder of a

system. A system with greater disorder has more entropy.o Compare the entropy of different

phases of matter

7.

o The concept of an ideal gas is a model to explain behavior ofgases.

o A real gas is most like an ideal gas when the real gas is at lowpressure and high temperature.

o Given a choice of pressure andtemperature conditions, identify thoseunder which gases behave most ideallyand/or least ideally

STUDY GUIDE

3

8.

o The Kinetic Molecular Theory (KMT) states that, for an IDEAL gas, all gas particlesa. are in random, constant, straight-line motionb. are separated by great distances relative to their size (have negligible volume)c. have no attractive forces between themd. have collisions that may result in a transfer of energy between them, but the total energy of the system

remains constant

9. o The Kinetic Molecular Theory (KMT) describes the

relationships of pressure, volume, temperature, velocity,frequency, and force of collisions among gas molecules.

o Explain the gas laws in terms of KMT.o Solve problems using the combined gas

law (Table T)o Recognize and draw graphs showing P

vs. T, V vs. T, and P vs. V

10. o Equal volumes of gases at the same temperature and pressure contain an equal number of particles.

4

Lesson 1: Review of Matter

Objective: To recall the vocabulary related to types and phases of matter.

What have we learned so far:

“ Stuff” is made out of particles. How the particles are put together and how they interact with each other and/or energyresults in either a physical or chemical change.

Particles are really called atoms and how they are put together causes physical property differences among elements. Weorganize elements in the Periodic Table based on similarities in their structure.

Elements interact with each other chemically to produce compounds. How these compounds are put together (ionicly orcovalently) determines their properties. We can represent these chemical changes with balanced equations andparticle diagrams.

Review of Matter

Matter: has definite Mass and occupies a definite Volume.

Pure Substance:o Element or Compound

Mixture:

o Homogeneouso Heterogenous

Matter is made of particles which behave in specific ways depending on their structure. Chemist’s study these propertiesto explain observations about the world around them. Now we will focus on the PHYSICAL PROPERTIES ANDCHANGES.

5

Recalling Information

1.) STP Not all substances have the same phase at the same temperature. Scientists had to develop a term to refer to talkabout substances under “normal” conditions. It is called STP. At STP Oxygen is a gas, while Cu is a solid.(SEE REFERENCE TABLE A)

STP= Temperature ___273K/0 °C____Pressure__101.3 kpa/1 atm____

2.) Phases

Phase Type of Particle Motion

(vibrating, rotating,and/or sliding)

Regular Geometric Arrangement of

Particles (position: fixed or not

fixed)

Strength of Particle Attractions

(weak, strong, or nonexistent)

Solid (s) vibrating fixed strong

Liquid (l) sliding not fixed) weak

Gas (g) rotating not fixed) nonexistent

3.) Phase Changes-Almost all substances can be made to change between the 3 phases, simply by altering theTEMPERATURE.

Properties can be physical or chemical; A phase change is a physical change.

6

Phase Change Name of Change

Solid to liquid (arrow E) Melting

Liquid to solid (arrow D) Freezing

Liquid to gas (occurs only whenthere is an open container)

Evaporation

Liquid to gas (occursthroughout the liquid) (arrow F)

Vaporization

Gas to liquid (arrow G) Condensing

Solid to gas Sublimation

Gas to solid Deposition

As temperature increases, particle motion increases/and the strength of particle attractions decreases.

7

Classwork 6-1:

_____1) Which of the following CAN be decomposed by chemical change?a) SO2 b) N2 c) Ne d) Al

_____2) Which of the following substances cannot be decomposed by chemical change?a) Na b) HNO3 c) ZnCl2 d) C6H12O6

_____3) Which of the following represents a homogeneous mixture?a) NaCl (s) b) NaCl (l) c) NaCl (aq) d) NaCl (g)

_____4) Which of the following represents a heterogeneous mixture?a) air b) soil c) salt water d) sugar

5) Draw a particle diagram of a compound of CaCl2, using black solid circles to represent the Ca and empty circles torepresent the Cl. Draw at least five molecules of CaCl2 in the box below:

_____6.) Given the particle diagram:

At 101.3 kPa and 298 K, which element could this diagram represent?(1) Rn (2) Xe (3) Ag (4) Kr

_____7.) Which statement best describes the shape and volume of an aluminum cylinder at STP?

(1) It has a definite shape and a definite volume.(2) It has a definite shape and no definite volume.(3) It has no definite shape and a definite volume.(4) It has no definite shape and no definite volume.

8

_____1. Which 5.0-milliliter sample of NH3 will take the shape of and completely fill a closed 100.0-milliliter container?(1) NH3(s) (3) NH3(g)(2) NH3(l) (4) NH3(aq)

_____2. Which of the following has the strongest forces of attraction?(1) CO2(s) (3) CO2(g)(2) CO2(l) (4) CO2(aq)

_____3. Which of the following can be compressed under pressure?(1) I2(s) (3) I2(g)(2) I2(l) (4) I2(aq)

_____4. Which 1.5-liter sample of salt does NOT take the shape of its container?

(1) NaCl(s) (3) NaCl(g)(2) NaCl(l) (4) NaCl(aq)

_____5. A 25.0 mL sample of water is poured from a 50.0 mL graduated cylinder to a 100.0 mL graduated cylinder. Thevolume of the water will

(1) increase(2) decrease(3) remain the same

_____6.) Which statement correctly describes a sample of gas confined in a sealed container?

(1) It always has a definite volume, and it takes the shape of the container.(2) It takes the shape and the volume of any container in which it is confined.(3) It has a crystalline structure.(4) It consists of particles arranged in a regular geometric pattern.

_____7.) In which material are the particles arranged in a regular geometric pattern?

(1) CO2 (g) (3) H2O(l)(2) NaCl(aq) (4) C12H22O11(s)

_____8.) Which grouping of the three phases of bromine is listed in order from left to right for increasing distancebetween bromine molecules?

(1) gas, liquid, solid (3) solid, gas, liquid(2) liquid, solid, gas (4) solid, liquid, gas

9

Lesson 2: Kinetic Molecular Theory (KMT) Basics

Objective: To relate average kinetic energy and IMF’s

I think you would agree that it is an established scientific fact that particles (molecules, atoms, ions)are in a constant state of random motion. This was first observed by Robert Brown in 1827, whonoticed that pollen grains suspended on the surface of water seemed to “dance about in a randomand unpredictable fashion.” However, in 1827, molecules and atoms had not yet been discovered. In1903, Albert Einstein published his first paper, which was an attempt to describe this “Brownianmotion” as the response of the pollen grains to collisions with water molecules (molecules and atomshad been discovered in the late 1800’s). This was Einstein’s introduction to the scientific community.Before this time, he was filling a job as an obscure clerk in the Swedish patent office. This paper later earned him the firstof two Nobel Peace Prizes in Physics (the other was for his more famous work in the area of relativity).

The “KMT” (Kinetic Molecular Theory) attributes the differences in the properties of the 3 phases of matter to differencesin particle (molecule or atom) motion. ENERGY associated with MOTION is referred to as “KINETIC ENERGY,” so the“Kinetic Molecular Theory” can simply be thought of as the “MOVING MOLECULE THEORY.” Temperature is defined asthe Average Kinetic Molecular Energy of a substance (how fast its particles are moving)

Check this out: Kinetic Molecular Theory animation

Particle Attractions-IMF!!!

Although it is important to compare the phases of matter from a properties standpoint, we can go a step further andexplain why the different phases of matter have the properties that they do from a kinetic molecular theory standpoint. Itreally has to do with Intermolecular forces of attraction, in other words, particles clinging to one another. Whencomparing a solid to a liquid or to a gas, the relative attraction between particles decreases. This should make sense if youthink about the particles in terms of energy.

Particles in a solid have little kinetic energy on average, compared to that of a liquid or a gas. Particles in a solid are simplyvibrating and thus remain close together and fixed in position. As heat energy is absorbed by a solid, the particles wiggleand vibrate in place more and more, until finally they have too much energy to stay put. The attractions between theparticles in the solid state are weakened as the particles gain energy. At this point the solid starts to melt.

As heat continues to be added, eventually all the solid particles are freed from their positions and can all move and flowpast one another, at which point we say the solid has completely melted. As the particles in the liquid state continue to beheated they move faster, as noted by the increase in temperature of the liquid (remember, temperature is a measure ofthe average kinetic energy of the particles in a sample). As the addition of thermal energy causes the molecules to movefaster and faster, eventually there comes a point where they can no longer attract each other at all. When this happens,the particles “escape” from each other, vaporizing into the gas state.

Relationship between IMF and Melting Points

You know from experience that different substances have different melting and boiling points. For instance, Group 1Elements have different melting points yet they are all in the same family (Alkali Metals). A graph of melting points of theGroup 1 elements is below.

http://www.youtube.com/watch?v=_rsqBNhFG1Y

10

Melting Points of Alkali Metals

0

100

200

300

400

500

0 10 20 30 40 50 60

Atomic Number

Melt

ing

Po

int

(K)

Heating a substance in the solid phase generally causes the temperature to increase. This causes the particles to vibrateand “wiggle” more. As the temperature increases, the particles have a harder time maintaining their attractions for eachother. When the forces of attraction are weak enough, melting starts to occur, and now the particles can start rotating andsliding past each other.

**

At normal atmospheric pressures, some substances can change directly from a solid to a gas. This change is calledsublimation. This is what occurs when ice cubes shrink in the freezer, or when a wash dries on a clothesline on a coldwinter day. Some substances, such as dry ice [CO2(s)], never pass through a liquid phase at standard pressure [101.3 kPa].A gas can also change directly to a solid. This is called deposition.

11

Classwork 6-2:

1. In terms of changes in Intermolecular forces of attraction and movement, what is the relationship between strengthof particle attractions and melting point temperature?

2. In terms of changes in kinetic and/or potential energy, what causes a solid to melt?

3. CO2 is a substance that sublimes(sg). What can be inferred about the strength of the attractions between CO2

molecules, as compared to a substance that melts instead?

12

Practice:

1. Kinetic energy is energy due to the motion of the particles in a material. The particles in a sample of matter havethree possible ways of moving: vibrating in place, rotating (spinning), and sliding past one another. These aredescribed in terms of kinetic energy.What is kinetic energy?

2. How particles are arranged (what phase they are in) is dependent on their energy and the effect this has on theirattractions for each other.What phase has the most energy and therefore the least attractions?

3. As particles gain energy, the attractions between them decrease. Why does this happen?

4. The strength of attractions between particles can be evaluated based on properties such as melting and boilingpoints, heat of fusion and heat of vaporization, and vapor pressure.Will a substance with low attractions have a low or high melting/boiling point? Explain.

13

Lesson 3A: Heat vs Temperature

Objective: To compare and contrast heat and temperature

What is heat? What is temperature? How are they different?

Energy:

Kinetic Energy (KE):

Potential (AKA Phase) Energy: energy of position (stationary or stored energy) associated with phase change, nottemperature change

Temperature:

NOTE: Although there is a direct relationship between temperature and heat, they are not the same thing!

Remember that “heat” is a form of energy, and that it is transferred from Sample A to Sample B (see below) only when the

particles in Sample A come into contact with the particles in sample B. The direction of heat flow is determined by thetemperature of the two samples.

2. What is TEMPERATURE? (Remember that we NEVER use the “f”-word in Chemistry!!! ºF!!!!)

You have probably long thought of temperature as just a measure of how hot or cold an object is. There isanother definition that chemists use: Temperature is

- Heat

- It can only be

- Heat is

Classwork 6-3A:

14

39

15

Lesson 3B: Heating/Cooling Curve

Objective: To apply changes in heat and temperature to phase changesHeating Curves:

As a substance is heated, its particles begin to move faster and spread apart. The speed of the particles is related to theirkinetic energy. The relative position of the particles is related to their potential energy. As solids, liquids, and gases areheated, most of the energy that is absorbed is converted to kinetic energy, and the temperature goes up. But as asubstance melts or vaporizes, the particle attractions weaken. As a result, the energy absorbed produces changes in thepotential energy of the particles, so the temperature does not change as the phase changes. The freezing point and themelting point of a substance are the same.

Cooling Curves:

As a substance iscooled, its particles begin to move slower and move closer together. The speed of the particles is relatedto their kinetic energy. The relative position of the particles is related to their potential energy. As solids, liquids, and gasesare cooled, most of the energy is released, and the temperature goes down. But as a substance condenses or freezes, theparticle attractions strengthen. As a result, the energy released produces changes in the potential energy of the particles,so the temperature does not change as the phase changes.The

16

MELTING, or “FUSION”: We can represent phase changes with particle diagrams. The following particle diagram represents melting.

Melting is also known as fusion, so chemists refer to the amount of energy needed to make a substance melt as the “heat of fusion”.

melting/fusion

The added energy decreases the attractions between particles, causing them to be less orderly, but still attracted to oneanother.

BOILING: We can represent phase changes with particle diagrams. The following particle diagram representsboiling. Boiling is a form of vaporization, so chemists refer to the amount of energy needed to make a substanceboil as the “heat of vaporization”.

vaporization

In this case, the added energy completely overcomes the attractions between particles, causing them to become totallydis- orderly in their conduct, with no attractions to one another.

Phase Changes are classified as ENDOTHERMIC or EXOTHERMIC.

ENDOTHERMIC =

EXOTHERMIC =

Summary

Lesson 3C: Phase ChangesObjective: To apply changes in heat and temperature to phase changes

THE Ice Cream PHASE CHANGE LAB Phase change - a change from one state (solid or liquid or gas) to another without a change in chemical composition

Purpose: • To investigate the effects of heat transfer on phase changes• To investigate the effects of temperature changes on physical changes

Question: How can this class cause a phase change to make ice cream from milk, sugar, salt, vanilla, ice and salt?

Background Information: In order to have a phase change in matter, heat must be gained or lost. Phase changes occur all around us in everyday life. For instance, ice melts when a drink is left in a room at normal temperature. Water freezes when placed in a really cold temperature, as in the freezer. In this experiment, we will see how fast heat is lost in order to change the milk from a liquid to a solid state. This is also an example of a physical change in matter.

Hypothesis: .

Materials: • 1 cup milk• ¼ cup sugar• 1/3 cup + 1 tsp salt• 1 ½ tsp vanilla• ice• measuring cups• measuring spoons• Ziploc bags (gallon and quart)• Tape• Towel

17

Procedure: 1. Place a dishtowel over your work area. Keep your work on your

towel.2. Measure and pour milk, sugar and vanilla flavoring into the small

Ziploc bag. Carefully seal the bag, tape it closed and shake up themixture.

3. Put the small bag into the larger Ziploc bag.4. In the large bag, add enough ice to cover the small bag and add the

salt.5. CAREFULLY SEAL THE BAG!!!!6. Take turns flipping the bag. Hold the bag by its corners. Keep

flipping over and over. Remember to keep the bag over the towel atall times. It should take about 10-15 minutes to freeze.

7. When you have ice cream, take the smaller bag out and wipe it dry.Dump the contents of the larger bag and into the bucket at yourstation. DO NOT DUMP IT DOWN THE DRAIN!!!

8. Dish out the ice cream equally into the cups and ENJOY!

Conclusion Questions: 1. What state of matter was the milk when you began?

2. What state of matter was the milk when you were finished?

3. In order to change the phase of milk, what had to be removed?

4. What happened to the heat energy that left the milk?

5. Why was the salt added to the ice?

6. If you did not add the sugar would the ice cream have frozen faster?

7. Why did the outside of the bag get wet?

8. Heat energy is needed to change phase from solid to liquid. List thepossible source of the heat needed for this phase change. Whichsource do you think is the best possibility and why?

9. Explain how the energy flow of the baggie system resulted in your tastytreat for the end product.

18

The Thermodynamics of Ice Cream

Pure water freezes at 0.0 °C (32 degrees F) & boils at 100.0 °C (212 degrees F). However, these values are changed by the presence of a solute (a minor component such as sugar, salt, etc.) in water.

Adding a solute, like salt, to water raises its boiling point from 100 ̊C to about 110 ̊C. The solutes dilute the number of water molecules at the surface of the water & thus more energy is required for the water to turn into a gas. This is called boiling point elevation. When you cook pasta in salted, boiling water, it will theoretically cook faster since it’s cooking at a higher temperature (110 ̊C vs 100 ̊C).

Adding a solute, like salt, to water also lowers the freezing point of water from 0 ̊C to about -10 ̊C or lower, thus the salt water has a lower freezing point than pure water and stays liquid at very low temperatures. When you add salt (or any other substance...sand, sugar) to water, it interferes with the orderly arranging of the water molecules into a solid and prevents the hydrogen bonds from forming. This is called freezing point depression.

Here are some common examples of these effects: Antifreeze lowers the freezing point and raises the boiling point of engine coolant (water). Salt is used to melt ice on the roads & keep it from re-forming.. The greater the concentration of the solute (salt), the lower the freezing point of water.

Definitions:

State of matter - the three traditional states of matter are solids (fixed shape and volume) and liquids (fixed volume and shaped by the container) and gases (filling the container)) "the solid state of water is called ice"

Solute - a minor component in a solution, such as sugar or salt in water.

Phase change - a change from one state (solid or liquid or gas) to another without a change in chemical composition

19

1. What is plotted on the x-axis and what is plotted on the y-axis of the graph?

2. During which line segments does temperature increase? ______________________

3. During which line segments is there no change in temperature? ______________________

4. If this substance were water, at what temperature would segment BC occur? ________

5. If this substance were water, at what temperature would segment DE occur? _________

Assignment: Investigating Phase Changes

1. Label each arrow (D, E, F, G) with the appropriate phase change (fusion/melting,

solidification/freezing, boiling, condensation)

2. Which arrows in Model 1 indicate the addition of energy? _______________________

3. Which term, endothermic or exothermic, is used to describe the situation when energy is

added into a system from the surroundings? _______________________

4. Which arrows in Model 1 indicate the release of energy? _______ and ________

5. What are the names of the phases changes shown above would be considered “exothermic?”

______________________ and ________________________

Model 1: Representations of Molecules in Three Phases

Model 2: A Plot of Temperature of a Substance as Heat is Added Over Time

These diagrams show how a substance responds when heat is added to it at a

steady rate, starting at a temperature below the melting point of the substance.

A cooling curve can be made to show how a substance responds when heat is

Classwork 6-3:

20

Assignment: Heating Curve

From this diagram identify the following:

1. The melting point temperature: ______

2. The boiling point temperature:______

3. The line segment where heat is being added, causing a change in the temperature of the solid phase: _______

4. The segment where heat is being added, causing a change in the kinetic energy of the particles when they are

in the liquid phase: ___________

5. The segment where heat is being added, causing a change in the speed of the particles when they are in the gas

phase: _____________

6. The segments where heat is being added but temperature is NOT changing: ________ & __________

7. The segments where heat is being added but kinetic energy is NOT changing: _______ & __________

8. The segments where added heat causes an increase in potential energy: ______ &______

9. The segment where heat is added, and might be called the “Heat of Fusion”: _________

10. The segment where heat is added, and might be called the “Heat of Vaporization:” _________

11. List all segments that represent exothermic processes: ________________________________________

12. List all segments that represent endothermic processes: _______________________________________

13. Is this substance water? ________ How do you know? ________________________________________

14. List all segments where particle attractions are decreasing: _____________________________________

15. List all segments where particle attractions are increasing: _____________________________________

16. Name the following phase changes:

BC _________________ CB _________________ DE __________________ ED _________________

21

Heating/Cooling Curve

As a substance is heated, its particles begin to move faster and spread apart. The speed of the particles is related to their kinetic energy. The relative position of the particles is related to their potential energy. As solids, liquids, and gases are heated, most of the energy that is absorbed is converted into kinetic energy and the temperature goes up. But as a substance melts or vaporizes, its particle spread out tremendously. As a result, the energy absorbed produces changes in the potential energy of the particles, so the temperature does not change as the phase changes. For that reason, the freezing point and the boiling point of a substance are the same.

Base your answers to the following questions on the graph which shows 10.0 kg of a substance that is a solid at 0˚C and is heated at a constant rate of 60 kilojoules per minute.

1. ________ What is thetemperature at which thesubstance can be both in thesolid and the liquid phase?

2. ________ During which letteredintervals is the internal potentialenergy of the substanceincreasing?

3. ________ During which letteredintervals is the kinetic energy ofthe particles increasing?

4. ________ How much heat isadded to the substance from the time it stops melting to the time it begins to boil?

5. ________ What is the total heat needed to melt the substance (starting at time 0)?

6. ________ What is the total heat needed to vaporize the substance (starting at time 0)

7. ________ What is the heat of vaporization of the substance?

8. ________ During which lettered intervals is the substance solid?

9. ________ During which lettered intervals is the substance in the liquid phase?

10. ________ During which lettered intervals is the substance in the vapor phase?

11. ________ What is the temperature at which the substance can be both in the liquid and thevapor phase?

12. Which segments represent an increase in kinetic energy? _____________________

13. Which segments represent kinetic energy staying the same? _______________________

14. Which segments represent an increase in potential energy? ________________________

15. Which segments represent potential energy staying the same? ______________________

16. Potential energy is stored energy. Where in a molecule is energy stored? ______________

Assignment:

12. Which segments represent an increase in kinetic energy? _________________________________

13. Which segments represent kinetic energy staying the same? ________________________________

14. Which segments represent an increase in potential energy? _______________________________

15. Which segments represent potential energy staying the same? _______________________________

16. Potential energy is stored energy. Where in a molecule is energy stored? _________________________22

23

Determine the line segment(s) that represents the information below.

a. Gas, only _________

b. Liquid, only _________

c. Solid, only _________

d. Solid and Liquid, only __________

e. Liquid and Gas, only __________

f. Melting Point _________

g. Boiling Point _________

h. Kinetic energy is increasing __________

i. Potential energy is increasing _________

24

From this diagram identify the following: a. The melting point temperature: ______

b. The boiling point temperature: ______

c. The line segment where heat is being added, causing a change in the temperature of the solid phase: ___________

d. The segment where heat is being added, causing a change in the kinetic energy of the particles when they are in the

liquid phase: ___________

e. The segment where heat is being added, causing a change in the speed of the particles when they are in the gas phase:_____________

f. The segments where added heat causes an increase in potential energy: ______ &______

g. The segment where heat is added, and might be called the “Heat of Fusion”: _________

So… Let’s compare Potential Energy and Kinetic Energy one more time. (Answer the following blanks with KE/PE and circle either increasing or decreasing.)

On the flat segments: ______ is constant and ______ is increasing / decreasing.

And on the diagonal segments: ______ is constant and ______ is increasing / decreasing.

_____ 2. As ice melts, its temperature remains at 0°C until it has completely melted. Its potential energy:(1) decreases (2) increases (3) remains the same

_____ 3. Which change of phase represents fusion?(1) gas to liquid (2) gas to solid (3) solid to liquid (4) liquid to gas

25

_____ 4. Which change of phase represents sublimation?(1) H2O(g) → H2O(l) (2) H2O(l) → H2O(s) (3) CO2(s) → CO2(g) (4) CO2(s) → CO2(l)

_____ 5. Which change of phase is exothermic?(1) gas to liquid (2) solid to liquid (3) solid to gas (4) liquid to gas

_____ 6. The heat of fusion for ice is 333.6 joules per gram. Adding 333.6 joules of heat to one gram of ice at STP willcause the ice to

(1) increase in temperature (3) change to liquid water at a higher temperature(2) decrease in temperature (4) change to liquid water at the same temperature

_____ 7. Which term can be used to describe the change of a substance from the solid phase to the liquid phase?(1) condensation (2) vaporization (3) evaporation (4) fusion

_____ 8. Which sample contains particles arranged in regular geometric pattern?(1) CO2(l) (2) CO2(s) (3) CO2(g) (4) CO2(aq)

9. The energy required to change 1 gram of a solid to a liquid at constant temperature is called its

“heat of __________________” value. It is a ___________________ property. (physical or chemical?)

Base your answers to questions 10 and 11 on the diagram below which represents a substance being from a solid to a gas, the pressure remaining constant

_____ 10. The substance begins to boil at point(1) E (3) C(2) B (4) D

_____ 11. Between points B and C the substance exists in(1) the solid state, only(2) the liquid state, only(3) both the solid and liquid states(4) neither the solid nor the liquid state

Lab–Heating&CoolingCurveforLauricAcid

27

PartA

1. Putonyourgogglesandlaboratoryapron.

28

PartADataTable

30

PartBDataTable

31

Graph:Use2differentcoloredpencilstoconstructtwographsonthesamesetofaxisthatwoulddescribetherelationshipbetweentimeandthetemperatureforthecoolingandheatingofthelauricacid.FOLLOWALLRULESOFGRAPHING.:

32

34

Lesson 4: Measurement of Heat Energy(Potential energy) during a temperature change:

Objective: To calculate heat during temperature changes

HEAT =

SPECIFIC HEAT (c)

The amount of heat LOST or GAINED in a physical or chemical reaction can be calculated using the following equation(found in Table T):

Example 1: How many joules are absorbed when 50.0 g of water are heated from 30.2C to 58.6C? q =?

m = 50.0gc = 4.18 J/g*C (see Table B)ΔT =58.6C - 30.2Cqq==((5500..00gg))((44..1188 J/g*C))((2288..44C)

q=

Lab activity: Specific Heat of a Metal

Background: The specific heat of a substance is the amount of energy needed to change the temperature of a standard mass of the substance (usually 1 gram) by one degree Celsius. It is a characteristic physical property and may be used to identify substances. Different substances have different specific heats. The relationship between energy, mass, temperature change, and specific heat is:

Q=mC ∆T Change in heat (∆H) is the amount of energy absorbed or lost by the substance. In this activity, ∆H will be measured in joules. A copper cylinder will be heated and cooled to find the specific heat of copper metal. Copper metal is commonly used as metal coating for pots, pans and hot water heating pipes.

Pre-lab Practice questions:

1. It was found, for an unknown substance, that 428.4 Joules of energy were required to heat 680 grams 5.00°C. What isthe specific heat of the unknown substance? Give appropriate units.

2. The specific heat of water is 4.2 J/g*°C. If the temperature of 56.0g of water drops from 34.0°C to 19.0°C, how manyJoules of energy were lost from the water?

Objective: To determine the specific heat of copper metal.

Materials: Copper rod, Bunsen burner, calorimeter, test tube, clamp, balance, calorimeter, tongs, 400mL beaker, ring stand, wire gauze, thermometer.

Safety: Safety Goggles, apron. Procedure:

1. Set up a hot-water bath by filling a 400mL beaker about half way with tap water and placing on a piece of wire gauzeon a metal ring attached to a ring stand. Set it so you burner can heat it. 2. Obtain a copper rod and measure its mass. Record it in the data table.3. When your water bath has begun to boil, using tongs gently place the metal into the hot water and continue heating.The sample should remain in the boiling for 6-7 minutes. While waiting, continue with the steps 4 & 5. 4. Obtain a calorimeter. Determine the mass of the calorimeter, lid and thermometer carefully. Record in your datatable. 5. Fill the calorimeter with distilled water until it is half full and then measure the mass of the calorimeter again plus thewater. 6. While keeping the metal in the water bath, carefully record the temperature of the boiling water. Since the metal hasbeen sitting in the water, we can assume that the temperature of the metal at this point is the same as temperature of the water. 7. Measure the temperature of the water in the calorimeter. Record in your data table.8. With tongs, carefully remove the metal from the boiling water and immediately place the metal piece into thecalorimeter. Avoid having droplets of hot water fall into the calorimeter. 9. With the thermometer or thermostat, gently stir the water in the calorimeter and record the highest temperaturereached. 10. Recover the metal by carefully pouring off the water and placing the sample on paper towel.11. Turn off your Bunsen burner and allow the water bath to cool.

35

Data:

Mass of copper rod

Mass of Calorimeter

Mass of Calorimeter plus water

Temperature of boiling water(copper rod)

Initial temperature of water in calorimeter

Final temperature of water in calorimeter

Calculations:

Mass of water in calorimeter

∆ Temperature of water ˚C (final-initial)

∆ H of water (Q=mC∆T)

Assuming that all the heat gained by the water came from the metal rod and that all of the heat lost by the metal rod went into the water; calculate the specific heat for copper.

∆ H of Metal ∆ H of Water mC∆T = mC∆T

∆ H of metal

Mass of metal

∆ Temperature of metal ˚C (final-initial)

Specific heat of metal(copper)

Analysis:

1. Did the water gain or lose energy? Explain.

2. Explain why the copper rod had a large change in temperature while the water had a small change in temperaturewhen they were placed together. (Hint: Look at their specific heats)

3. In terms of molecular motion, what was happening to the speed of the molecules in the water when the copper rodwas added? What happened to the speed of the molecules of the copper rod?

4. Calculate your percent error for the specific heat of copper. (Accepted value=0.382 J/g*˚C)

36

Lab conclusion: Specific Heat of a Metal

1. Write a paragraph summarizing what you have learned about the scientific concept of the lab from doing thelab. Back up your statement with details from your lab experience.

2. Object A at 40ºC and object B at 80ºC are placed in contact with each other. Which statement describes theheat flow between the objects?

A) Heat flows from object A to object B.B) Heat flows from object B to object A.C) Heat flows in both directions between the objects.D) No heat flow occurs between the objects.

3. An iron bar at 325 K is placed in a sample of water. The iron bar gains energy from the water if

the temperature of the water is

A) 65 K B) 45 K C) 65°C D) 45°C

4. The average kinetic energy of water molecules is greatest in which of these samples?

A) 10 g of water at 35°CB) 10 g of water at 55°CC) 100 g of water at 25°CD) 100 g of water at 45°C

5. In an experiment using a calorimeter, the following data were obtained:

What is the total number of Joules absorbed by the water?

A) 1,000 B) 1,500 C) 6,300 D) 4,500

37

Worksheet- Introduction to Specific Heat Capacities Heating substances in the sun: The following table shows the temperature after 10.0 g of 4 different

substances have been in direct sunlight for up to 60 minutes.

Time (minutes) Air (° C) Water (° C) Sand (° C) Metal (° C)

O (initial) 25°C 25°C 25°C 25°C

15.0 min 28.9°C 26.2°C 30°C 35°C

30.0 min 32.5°C 27.5°C 35°C 45°C

45.0 min 36.2°C 28.8°C 40°C 55°C

60.0 min 40°C 30°C 45°C 65°C

Step 1: Create a line graph for each substance on graph below.Use colored pencils.Label the substances.

Step 2: Answer questions 1. Order the substances based

on the time required to heatthem from :

slowest

fastest

2. Which do you think willcool the fastest?Explain

3. When you boil water in a pot on the stove, which heats faster, the metal or the water? Explain.

4. Why do you think different substances heat up and cool down at different rates?

***Specific heat capacity = the amount of heat needed to raise the temperature of 1 g of a

substance by 1 degree. ***

5. Based on the definition above, which of the 4 substances do you think has:

a) the highest specific heat capacity? b) the lowest heat capacity?

6. Here are the heat capacities of the four substances: 4.18 J/g °c, 1.00 J/g °c, 0.80 J/g °c,

& 0.60 J/g °c. Match & then label each substance with its specific heat capacity on the graph.

7. If something has a high specific heat capacity will it take a lot of heat or a little heat to change its

temperature? Explain. (careful! Use the definition, your graph, and the data from #6)

8. Assuming they both start at the same temperature, which will heat up faster, a swimming pool or a bath tub?

Explain your thinking.

Classwork 6-4:

38

1. For q= m ●c ● Δ T : identify each variables by name & the units associated with it.

2. Heat is not the same as temperature, yet they are related. Explain how they differ from each other.

a. Perform calculations using: (q= m ●c ● Δ T) b. Determine if it’s endothermic or exothermic

1. Gold has a specific heat of 0.129 J/(g×°C). How

many joules of heat energy are required to raise

the temperature of 15 grams of gold from 22 °C to 85

°C?

Endothermic or exothermic?_______________

2. An unknown substance with a mass of 100 grams

absorbs 1000 J while undergoing a temperature increase

of 15 °C. What is the specific heat of the substance?


3. If the temperature of 34.4 g of ethanol increases

from 25 °C to 78.8 °C, how much heat has been absorbed

by the ethanol? The specific heat of ethanol is 2.44

J/(g×°C)


4. Graphite has a specific heat of 0.709 J/(g×°C). If a

25 gram piece of graphite is cooled from 35 °C to 18 °C,

how much energy was lost by the graphite?


5. Copper has a specific heat of 0.385 J/(g×°C). A piece

of copper absorbs 5000 J of energy and

undergoes a temperature change from 100 °C to

200 °C. What is the mass of the piece of copper?


6. 45 grams of an unknown substance undergoes a

temperature increase of 38 °C after absorbing

4172.4 Joules. What is the specific heat of the

substance? Look at the table on page 513 of your

book, and identify the substance.


7. A 40 g sample of water absorbs 500 Joules of energy.

How much did the water temperature change? The

specific heat of water (liquid) is 4.18 J/(g×°C).


8. If 335 g of water at 65.5 °C loses 9750 J of heat,

what is the final temperature of the water? Liquid

water has a specific heat of 4.18 J/(g×°C).

Endothermic or exothermic?_______________ 2.

39

9.

10.

11.

12.

13.

14.

15.

16.

40

41

Lesson 5: Measurement of Heat Energy(Potential energy) during a phase change:

Objective: To calculate heat during phase changes

Example: How many joules are required to melt 255 g of ice at 0C?

Heat of Vaporization (Hv)

Hv=2260 J/g

Heat of Fusion (Hff)

Hf=334 J/g

Hf=334 J/g Hv=2260 J/g

Example: How many kilojoules of energy are required to vaporize 423 g of water at 100 C?

q = mHf

q =

q = mHvq =

42

HHooww aarree tthheessee ffoorrmmuullaass aapppplliieedd ttoo aa hheeaattiinngg ccuurrvvee??

NNoottiiccee tthhaatt dduurriinngg pphhaassee cchhaannggeess tthheerree iiss ccoonnssttaanntt tteemmppeerraattuurree tthheerreeffoorree iitt iiss nnoott iinncclluuddeedd iinn tthhee ccaallccuullaattiioonn.. DDuurriinngghheeaattiinngg pphhaasseess,, cchhaannggee iinn tteemmppeerraattuurree iiss ppaarrtt ooff tthhee ccaallccuullaattiioonn!!

Heat of Vaporization

Prelab Questions 1. Define heat of vaporization.

2. If a substance’s heat of vaporization depends on its molecular mass, which would youexpect to vaporize faster, a heavy molecule or a lighter one? This will be hypothesisone.

3. If a substance’s heat of vaporization depends on its molecular mass, which would youexpect to vaporize faster, a molecule with strong intermolecular forces, or weakintermolecular forces? This will be hypothesis two.

4. Based on these two hypotheses you just made, fill in the table below, ranking eachsubstance from fastest to slowest vaporization based on each of the two predictionsmade above. These predictions will be tested during the lab.

Substance Molar mass

(g/mol)

% of bonds that are polar

# of polar bonds

# of total bonds

Strongest intermolecular

forces (hydrogen

bond, dipole-dipole, or London

dispersion forces)

Rank polarity

1 = least 5 = most

Hyp #1 prediction 1 = fastest 5 = slowest


Water

Ethanol

Pentane

Acetone

Ethylene glycol

43

Table of Substances

Purpose To determine whether a substance’s heat of vaporization depends on its molar mass, on the strength of its intermolecular forces, or both.

Safety Always wear safety goggles when working with chemicals in a laboratory setting.

Materials • Hot plate• Aluminum foil• Pipette• Safety goggles• Samples of each of the following chemicals:

o Watero Ethanolo Pentaneo Acetoneo Ethylene glycol

Procedure 1. Cover the top of the hot plate with aluminum foil. Crimp the edges so that the foil is

secured to the top of the hot plate. (The hot plate should not be turned on yet!) 2. Turn the hot plate to 100 and wait about five minutes for the hot plate to warm up3. Have one group member place a small drop of the chemical you are testing on the foil.

(Hint: some of the liquids have very little surface tension, so they tend to run out of thepipette even if you don’t squeeze it. Be careful with these.) Have a different groupmember use a stopwatch to time how many seconds it takes for the drop to evaporatecompletely.

4. If five minutes pass and a drop still hasn’t evaporated, just write “>five min.” and stoptiming. Record your data.

5. Repeat this process with the other chemicals.6. Turn off and unplug the hot plate.

Results/Observations

Substance Seconds to evaporate


Hyp #e prediction 1 = fastest 5 = slowest

Actual 1 = fastest 5 = slowest

Water

Ethanol

Pentane

Acetone

Ethylene glycol

45

Analysis 1. Which hypothesis is a better fit for your data?

2. Does either hypothesis fit your data perfectly? If not, which molecule(s) did not fit?

3. What factor(s) do you think explain the vaporization time of ethylene glycol?

4. Discuss the validity of your experiment. Do you believe your results? Why or why not?How did your results compare with those of other groups? (i.e. did you get yourmolecules in the same order as others?) How good were your lab techniques and yourfollowing of directions?

46

1.

2.

3.

4.

5.

6.

47

Introduction: Calorimeters are instruments that measure temperature changes in closed systems.

From these temperature changes we can calculate the amount of heat that is absorbed or released by the water from the calorie formula:

Q = m c ΔT Table T of Reference Tables

This equation is used exclusively when there is a temperature change or a non phase change. At a phase change, we can calculate how much heat is absorbed or released by using the same formula but adding the appropriate constant. For example if we wanted to know how much energy (heat) is absorbed when ice melts, we use the following formula:

Q = m X Hf Value given on Table B

The Heat of Fusion (Hf) for water is 334 J/g. That is for every gram of ice it takes 334 joules of heat to be absorbed to completely melt it to the liquid phase. It also represents the amount of joules that must be released when one gram of H2O (l) freezes to the solid phase.

In this lab we will experimentally calculate the heat of fusion of ice by dropping a known mass of ice into a calorimeter filled with a known mass of water. By taking the initial and final temperatures and using the OLD formula for heat, we can calculate the amount of joules absorbed by the ice. Joules per gram is calculated by dividing the joules by the mass of the ice and this number will represent the experimental Heat Of Fusion for H2O (s).

Objectives:

Materials: 1. Ice cube2. Thermometer3. Calorimeter4. Tap water

Procedure: 1. Quickly mass out an ice cube. 2. Measure 150 ml of tap water that has been at room temperature and place in calorimeter. Ask your instructor where the room temperature water is located. 3. Take the initial temperature of water before ice cube is placed in the

water in the calorimeter. 4. Place ice cube in calorimeter and close lid.5. Record the coldest final temperature of the water in the calorimeter.6. Complete data table and calculate the heat of fusion for water.

Lab - Heat of Fusion of Ice

To experimentally determine the the value for the heat of fusion of ice and calculate your Percent Error using the formula on Table T

48

1.Mass of ice cube:……………..………..….……_______________

2.Mass of Styrofoam calorimeter………………._______________

3.Grams H2O in calorimeter:…….……..……….._______________

4.Initial temperature of water:……...……………_______________

5.Final temperature of water……………………._______________

6.Change in Temperature…………………………______________

7.joules of heat absorbed by Ice…..……………_______________

8.joules of heat absorbed per gram of ice:…..._______________

9.Measured heat of fusion:…………………..…._______________

Calculate percentage of error:…………….

Show all work here: Use your measured value(Data #9) and the accepted valuefor the Heat of Fusion found on Table B to calculate your percent error using the formula below.

49

1. What is the definition of a joule?

2. Calculate the amount of joules needed to completely melt a 75 gram piece of iceat 0°C ?

3. Calculate the amount of joules absorbed when 75 grams of water vaporizes at100°C.

4. Calculate the amount of joules needed to change the temperature of 75 grams ofwater from 0°C to 100°C

5. Calculate the amount of joules needed to completely to vaporize a 75 gram icecube at 0°C.

6. Convert your answer to kj from question 5.

7. When heat energy is lost by a pure substance at its freezing point with no change

in temperature, its potential energy _________________. (increases, decreases, remains the same)

8. The heat of fusion for ice is 334 joules per gram. Adding 334 joules of heat to1 gram of ice will cause the ice to

1) increase in temperature (2) decrease in temperature 3) change to water at a higher temperature (4) change to water at the same temperature

Using Reference Table B & T answer the following questions. Show ALL Calculations!!

50

51

Lesson 6: Vapor Pressure & Boiling Point Temperature

Objective: To relate vapor pressure to boiling points. To determine the boiling point of a substances using reference

table H

Vaporization is different from freezing or melting, because some vaporization occurs at all temperatures of a liquid.

The process of vaporization(It can happen in a solid too – sublimation!)

After vaporization, the molecules that are left behind have a lower average kinetic energy than the original, so thetemperature has decreased.

The amount of vaporization is dependent on the temperature of the liquid and on the kind of liquid.

The higher the temperature the more vaporization occurs The weaker the intermolecular attractions, the easier molecules escape, the lower the boiling point. The more vaporization at a given temperature, the more cooling you get.

Boiling is when

Vapor pressure

Boiling occurs when the

Finally when the vapor pressure above a liquid gets to be the same as the pressure of the atmosphere, that is, the temperature is hot enough, boiling occurs.

Vapor pressure can only be measured if the container is closed so that a condition called “dynamic equilibrium” can beestablished between the vapor and the liquid. The relationship between vapor pressure and temperature is direct. Forany liquid, this means that as the temperature of the liquid increases, the rate of evaporation increases. The vaporpressure and atmospheric pressure has to be equal in order for BOILING to occur.

52

Using Table H Table H of your Reference Tables shows the vapor pressures of four common liquids as a function of temperature.

Vapor pressure and Intermolecular Forces of Attraction (IMF)

- Remember vapor pressure is the- The- Use Reference Table H to

53

Lab Activity - Vapor Pressure

Why? The vapor pressure of a substance depends on the temperature (higher temperature leads to higher vapor pressure). A liquid boils when the vapor pressure equals the atmospheric pressure. Water boils at 100 o C at sea level, but in Denver, Colorado, which is a mile high and has lower atmospheric pressure than at sea level, water boils at a different temperature. Certain substances, such as nail polish and paint, dry quickly because they have high vapor pressures.

Learning Objectives • Understand the relationship between vapor pressure and temperature.• Relate the vapor pressure of a substance to its boiling point.• Use a vapor pressure curve to describe the relative strength of the intermolecular forces

between the molecules of a substance. Model 1

Task Place an equal amount of ethanol (CH3CH2OH), acetone (CH3COCH3, nail polish remover), and water on three separate cotton balls. Wipe the cotton balls on the desk at the same time. Observe the relative rate of evaporation for the liquids. Record your observations below.

54

Observations:

Key Questions 1. Which liquid evaporated at the fastest rate?

2. Which liquid evaporated at the slowest rate?

3. Draw the structural formulas for all three molecules.Ethanol: Acetone: Water:

4. How do the intermolecular forces in acetone compare to the intermolecular forces found inwater? Support your answer with an explanation.

5. Which of the three liquids has the strongest intermolecular forces of attraction? Support youranswer with an explanation.

6. Based on your observations, which liquid has the highest vapor pressure? Explain your answer.

7. Using your answers to questions 4, 6 and 6, explain how intermolecular forces influence thevapor pressure of a liquid.

Predict which of the three liquids used in this task would have the highest boiling point.Support your answer with an explanation.

8.

��

1 . Which substance has the lowestvapor pressure at 75°C?

(1) water(2) ethanoic acid(3) propanone(4) ethanol 1____

2. According to Reference Table H, what is the vapor pressure of propanone at 45°C?

(1) 22 kPa (3) 70. kPa (2) 33 kPa (4) 98 kPa 2____

3. The boiling point of a liquid is thetemperature at which the vapor pressureof the liquid is equal to the pressure onthe surface of the liquid. What is theboiling point of propanone if the pressureon its surface is 48 kilopascals?

3____

4. At which temperature is the vaporpressure of ethanol equal to the vaporpressure of propanone at 35°C?

4____

5. As the temperature of a liquid increases, its vapor pressure

(1) decreases (2) increases (3) remains the same 5

6 . As the pressure on the surface of a liquid decreases, the temperature at which the liquid will boil

( 1) decreases (2) increases (3) remains the same 6

7. Using your knowledge of chemistry andthe information in Reference Table H,which statement concerning propanoneand water at 50°C is true?

(1) Propanone has a higher vaporpressure and stronger intermolecular forces than water.

(2) Propanone has a higher vapor pressure and weaker intermolecular forces than water.

(3) Propanone has a lower vapor pressure and stronger intermolecular forces than water.

(4) Prop an one has a lower vapor pressure and weaker intermolecular forces than water.

7

8. A liquid boils when the vapor pressure of the liquid equals the atmospheric pressure on the surfaceof the liquid. Using Reference Table H, determine the boiling point of water when the atmosphericpressure is 90. kPa.

Classwork 6-6:

55

Base your answers to question 9 using your knowledge of chemistry and on the graph below, which shows the vapor pressure curves for liquids A and B. Note: The pressure is given in mm Hg - millimeters of mercury.

800

700

600 0) I

500 E S ! 400::::I til til 300 !Do

200

1 00

v I / �

I I / "

J AI V J I � V )

/� ..... V �

� , "". ........ � -........

o o 1 0 20 30 40 50 60 70 80 90 1 00 1 10 120

Temperature (0C)

9 . a) What is the vapor pressure of liquid A at 70°C? Your answer must include correct units.

b) At what temperature does liquid B have the same vapor pressure as liquid A at 70°C?Your answer must include correct units.

c) At 400 mm Hg, which liquid would reach its boiling point first? ___________ _

d) Which liquid will evaporate more rapidly? Explain your answer in terms ofintermolecular forces.

56

10. At 65°C, which compound has a 15 . The table below shows the normal vapor pressure of 58 kilopascals? boiling point of four compounds.

( 1 ) ethanoic acid (3) propanone (2) ethanol (4) water 10

1 1 . Which liquid has the highest vapor pressure at 75°C?

( 1) ethanoic acid (3) propanone (2) ethanol (4) water 1 1

12. When the vapor pressure of water is70 kPa the temperature of the water is

(3) 60°C (4) 9 PC

13. According to Reference Table H, what is the boiling point of ethanoic acid at 80 kPa?

(3) 1 1 1 °C (4) 1 25°C

1 2

1 3

14. The graph below shows the relationshipbetween vapor pressure and temperaturefor substance X.

� -; 2.0 � 1 .5

e! 1 .0 � 0.5 8. 0

I ........

/ 1/ /'

� 10 20 30 40 50 Temperature (0C)

What is the normal boiling point for substance X?

14

Compound Normal Boiling Point (0C)

HF(C) 1 9.4

CH3CI(C) -24.2

CH3F(C) -78.6 HCI(C) -83.7

Which compound has the strongest intermolecular forces?

( 1 ) HF(t) (2) CH3CI(t)

(3) CH3F(t) (4) HCI(t)

1 6 . Based on Reference Table H, which subtance has the weakest intermolecular forces?

( 1 ) ethanoic acid (2) ethanol (3) propanone (4) water

15

1 6

17. The graph below represents the vaporpressure curves of four liquids.

_ 80 CI ::I: 70 E 60 E -; 50 5 40 :I 30 CD � 20 l) 10CI.

A B C D

m o r.-,,,'-�-r.-,,-'� ::> 0 10 20 30 40 50 60 70 80 90 100 110 120 Temperature (OC )

Which liquid has the highest boiling point at 600 mm Hg?

( 1 ) A(2) B

(3) C (4) D 17

57

18. A liquid's boiling point is the temperature at which its vapor pressure is equal to the atmosphericpressure. Using Reference Table H, what is the boiling point of prop an one at an atmosphericpressure of 70 kPa?

19. Explain, in terms of molecular energy, why the vapor pressure of prop an one increases when itstemperature increases.

20. The boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal tothe pressure on the surface of the liquid. The heat of vaporization of ethanol is 838 joules per gram.A sample of ethanol has a mass of 65.0 grams and is boiling at 1 .00 atmosphere.

Based on Table H, what is the temperature of this sample of ethanol? _________ _

2 1 . A sample of ethanoic acid is at 85°C. At a pressure of 50 kPa, what increase in temperature is needed to reach the boiling point of ethanoic acid? ____ _

22. Based on Reference Table H, which substance has the:

strongest intermolecular forces - ___________ _

weakest intermolecular forces --------------

23. At 70 kPa, determine the boiling point of:

propanone -_______ °C

ethanol - °C --------

water - °C ---------

ethanoic acid - °C ------

58

59

Lesson 7: Real vs. Ideal gases

Objective: To compare the properties of real and ideal gases

Gases & Entropy Entropy =

… increases when…

*

Comparing States of Matter: solids, liquids, & gases

Particle arrangement:Close, Ordered, vibrate in

place

Intermolecular forces ofattraction: high

Shape: definite

Volume: definite

Entropy:

Particle arrangement:Less ordered, flow around

eachother

Intermolecular forces ofattraction: medium

Shape: takes shape ofcontainer

Volume: definite

Entropy:

Particle arrangement:Far apart; DISORDER; random

movement

Intermolecular forces ofattraction: low

Shape: takes shape ofcontainer

Volume: explands to fillcontainer

*

Entropy:

*

. IDEAL vs. REAL Gases

Ideal Gas

-

-

-

-

Real Gas

-

-

-

-

Unit 6 PBOM - Part 2 Gases & the Gas Laws

60

Gases behave most ideally BECAUSE

a. particles are moving faster AND

b. particles are farther apart

Gases deviate (stray) from ideal BECAUSE

1. particles are moving slower AND

2. particles are closer together

*

Kinetic Molecular Theory (KMT) -

Less chance of gas particles attracting

each other

gas particles will attract each other

Activity - Gas Pressure

Background Pressure is caused by the number of collisions between molecules and the force of these collisions. When there are more collisions, the pressure is higher. There are three things that can affect the number of collisions.

1) Size of the container2) Temperature3) Number of moleculesYou will look at how these three factors affect the number of collisions and

therefore affect the pressure of a gas.

Procedure For each of the following parts, you will need a long rope and four students to hold the rope in a square shape. Each student holding the rope will count the number of “gas molecules” (student volunteers) that collide with the wall of the container during a time period of one minute for each trial.

Gas molecules should remember the following: 1) Gas molecules travel in straight path until acted upon by the wall of the container

or another gas molecule. They do not turn to avoid or cause a collision. 2) Gas molecules move at constant random motion. So you should not change your

speed or stop during the duration of a trial. 3) Gas molecules are not attracted to or repelled by each other. So you should not

change directions to hit your classmates.

PART A Container size and pressure: Gas molecules should move at room temperature.

Container Size Number of collisions Trial 1 Trial 2 Average

Small container

Large container

PART B Temperature and pressure: Gas molecules should speed walk for high temperature and walk slowly for low temperature.

Temperature Number of collisions Trial 1 Trial 2 Average

High Temperature

Low Temperature

62

PART C Number of molecules and pressure

Analysis 1) What two things causes pressure in gases?

2) Out of the three factors that affect pressure, which do you think would affect thepressure the most? Why?

3) As you increase the size of a container, what happens to pressure?

4) As you decrease the number of gas particles, what happens to pressure?

5) As you increase the temperature, what happens to pressure?

6) As temperature decreases, what do you think would happen to the volume of thecontainer?

Number of Molecules

Number of collisions Trial 1 Trial 2 Average

5 molecules

10 molecules

63

64

Activity - Balloon and Flask

Prelab question Read the procedure and predict what will happen. Justify your prediction.

Procedure 1. Pour about 25 mL of water into the flask.

2. Heat the water on a hot plate until it boils. Allow it to boil for about two moreminutes. Turn off the hot plate. There should still be water in the flask.

3. Using tongs or something to protect your hands, remove the flask from the hotplate and pour the water out.

4. Immediately place a balloon over the mouth of the flask.

5. Place the flask on the table and record observations.

Observations

Analysis Using arrows, sketch the molecules inside and outside of the flask that make up the air during four points in this experiment (see below). Add the balloon and what it looks like,

when appropriate. Use arrows to indicate particles, and longer arrows to indicate faster moving molecules.

Room temperature Boiling water With balloon, With balloon, after heating cooled

Conclusion What did you learn from this experiment about temperature, pressure, and volume of

gases?

Lab Activity: Gas Laws

Background: In a gas, particles are spread far apart; therefore a gas takes up more volume than a solid or a liquid. For example, water in the form of steam takes up about 2000 times the volume that the same amount of water does in liquid form. There are many formulas to describe the behavior of a gas under certain conditions. Boyle’s law (P1V1=P2V2

) states that the pressure is inversely proportional to the volume. Charles law (V1/T1=V2/T2), states that volume is directly proportional to temperature. Gay-Lussac’s Law ( P1/T1 =P2/T2) states that pressure is directly proportional to temperature. Applying these laws together gives us the combined gas law:

P1V1=P2V2

T1 T2

Objective: To observe gas laws in action!

Safety: Goggles

Materials: syringe, soda can, Bunsen burner(hot plate), iron ring, wire gauze, matches, large beaker(600mL), ice, mini marshmallows, shaving cream, vacuum pump, pen, tongs, medium size balloon, 250 ml flask, small balloon filled with air.

Pre-Lab:

1. A cylinder with a movable piston contains a sample of gas having a volume of 6.0 liters at 293 K and 1.0 atmosphere.What is the volume of the sample after the gas is heated to 303 K, while the pressure is held at 1.0 atmosphere?

Part I. Soda Can Crush

Procedure: 1. Obtain a large beaker (600 mL) and fill it ¾ full with COLD tap water.2. Obtain an aluminum can and add 7-10mLs of water.3. Place the can on a heating set up (hot plate or wire gauze/ring stand) and heat until a steady stream of steam flowsout of the can. 4. Using beaker tongs grab the aluminum can near the bottom of the can and quickly turn it upside down into the beakerof water. 5. Observe. Lift can out of beaker of water. Observe.

Analysis:

1. What happened to the can?

2. What did you observe when you removed the can from the beaker?

3. Fill in:

When the can was heated, the water turned to __________, which takes up ________(more/less) volume than liquid water. When the can was inverted into the water in the beaker, this created a closed system. The temperature inside the can _____________(increased/decreased), causing the steam to change from gas state to __________state. A partial vacuum was created causing the pressure inside the can to be _________________(greater/less) than the pressure outside the can. Therefore, the can filled with water from the beaker.

65

Part II: A Happy Marshmallow

Procedure 1. Take a mini marshmallow and draw a smiley face on one side with the felt tip pen provided.2. Take the syringe and remove the plunger using a twisting motion.3. Insert the mini marshmallow and put the plunger back but DO NOT squish the marshmallow!!!4. Push the plunger down until it almost touches the marshmallow. Put your index finger on the pointy opening of thesyringe so that it is airtight. With your other hand, pull the plunger out (slowly) and observe the smiley face. 5. Release your index finger. Note what happens to the marshmallow.6. Pull the plunger out to near the top of the syringe. Again, put your index finger over the pointy end opening to make itairtight and use your other hand to slowly push the plunger in toward the marshmallow. Observe the smiley face. 7. Release the pressure by removing your index finger. Observe what happens to the marshmallow.

Analysis:

1. What is the relationship you observed between volume and pressure?

2. In terms of the kinetic molecular theory, what is happening to the particles as the pressure varies?

66

Lab conclusion: Gas Laws

1. Write a paragraph summarizing what you have learned about the scientific concept of the lab from doing thelab. Back up your statement with details from your lab experience.

2. When a sample of a gas is heated at constant pressure, the average kinetic energy of its molecules

A) decreases, and the volume of the gas increasesB) decreases, and the volume of the gas decreasesC) increases, and the volume of the gas increasesD) increases, and the volume of the gas decreases

3. Under which conditions of temperature and pressure does oxygen gas behave least like an ideal gas?

A) low temperature and low pressureB) low temperature and high pressureC) high temperature and low pressureD) high temperature and high pressure

4. Which graph represents the relationship between pressure and volume for a sample of an ideal gas atconstant temperature?

a. b. c. d.

5. Which graph shows the pressure-temperature relationship expected for an ideal gas?

a. b. c. d.

67

68

Lesson 8: Gas Laws

Objective: To select and apply the proper formula to calculate pressure, temperature or volume changes in a gas.

Avogadro’s Law:

Gas Laws Here’s an easy way to remember the relationship between pressure, temperature, and volume. NOTICE how the variablesare written from left to right in alphabetical order. Place your finger on whatever variable remains constant, then rotate thevariable you want to change up or down. Watch what happens to the third variable as a result.

P T Va.

b.

c.

When either P, T, or V is held constant for a gas:

Boyles Law (Constant Temperature):Example: decreasing P on marshmallow will increase V

P1V1 = P2V2

---

CO2

100 torr

5.0 L

800 K

H2

100 torr

5.0 L

800 K

Ar

100 torr

5.0 L

800 K

Pressure (atm)

MEMORIZE!!!!!

69

EXAMPLE: A sample of nitrogen gas occupies 250 mL at STP. What will the new volume of the gas be at 2 atmospheres,

with temperature remaining constant?

V1 = 250mL V2 = ? P1 V1 = P2 V2

P1 = 1 atm P2 = 2 atm 1 atm (250mL) = 2 atm (V2)

T1 = 273 K T2 = 273 K 2 atm 2 atm

(since temperature is constant,

we do not have to use it in the equation)

_________________________________________________________Charles Law (Constant Pressure):

t Example: The volume of an ideally behaving gas is 300 L at 227°

C.Example 2: Aerosol cans with gases under high pressure can’t be near high temp or contents willexpand and the bottle will explode

V1 = V2 always use K!

T1 T2

Convert ˚C to K K = ˚C + 273

Example: While the pressure on 670mL of chloine gas remained steady, the temperature was changed from 24˚C to 0˚C.

What change in volume resulted?V1 = 670mL V2 = ? V1 = V2 670mL = V2

P1 = P2 = T1 T2 297K 273K

T1 = 24 +273 =297K T2 = 0 +273 = 273K

(since pressure is constant, we do not have to use it in the equation) (273K)(670mL)= V2

297K

Temperature (K)

70

________________________Gay Lussac’s Law (Constant Volume)

P1 = P2 always use K!

T1 T2 (Convert ˚C to K)

K = ˚C + 273

Example: A 3.0 mL rigid container is filled with helium gas at a temperature of 150K. The pressure in the container is

167 kPa. If the pressure is increased to 381 kPa, what is the container’s new temperture?

V1 = 3.0mL V2 = 3.0mL P1 = P2 167kPa = 381kPa

P1 = 167kPa P2 = 381kPa T1 T2 150K T2

T1 = 150K T2 = ?

(since volume is constant, we do not have to use it in the equation) (381kPa (150K)) = T2

167kPa

Temperature (K)

71

Lesson 9: Combined Gas Laws

Objective: To apply the combined gas law to calculate changes in temperature, pressure or volume of a gas.

Combined Gas Law:

If we combine the three gas laws we get the combined gas law. Look it up on Reference Table T

Some things to note when using this law… 1.)2.)3.)

Example: 300 Liters of acetylene gas were measured at a temperature of 273 K and 1 atm. The gas was thensubjected to a pressure of 3.15 atm and the temperature rose to 281 K. What new volume did the gasoccupy?

V1 = 300L V2 = ? P1 V1 = P2V2

P1 = 1atm P2 = 3.15atm T1 T2T1 = 273K T2 = 281K(since no variable is constant, all must be used in equation) (1 atm )(300L) = (3.15atm)( V2)

273K 281K

(1atm)(300L)(281K) = V2

(273K) (3.15 atm)

*cancel out your units 84300 atm·L·K = V2

859.95 atm·K

1 . Standard pressure is equal to

( 1 ) 1 atm (2) 1 kPa

(3) 273 atm (4) 273 kPa

2. The volume of a gas is 4.00 liters at

1

293 K and constant pressure. For thevolume ofthe gas to become 3.00 liters,the Kelvin temperature must be equal to

3.00 x 293 3.00 x 4.00 ( 1 ) 4.00 (3) 293

4.00 x 293 293 (2) 3.00 (4) 3.00 x 4.00 2

3. Which graph best represents the pressurevolume relationship for an ideal gas atconstant temperature?

( 1 ) V � (3)VlQ p p

(2) v IL (4)VL 3

p p

4. As the temperature of a gas increases atconstant pressure, the volume of the gas

( 1 ) decreases(2) increases(3) remains the same 4

5. A sample of helium gas has a volumeof 900. milliliters and a pressure of2.50 atm at 298 K. What is the newpressure when the temperature ischanged to 336 K and the volume isdecreased to 450. milliliters?

( 1 ) 0. 1 77 atm (3) 5.64 atm(2) 4.43 atm (4) 1 4. 1 atm 5

6. A rigid cylinder with a movable pistoncontains a 2.0-liter sample of neon gas at STP. What is the volume of this samplewhen its temperature is increased to30.0C while its pressure is decreasedto 90. kilopascals?

( 1 ) 2.5 L(2) 2.0 L

(3) 1 .6 L (4) 0.22 L 6

7. A sample of oxygen gas in one container has a volume of 20.0 milliliters at 297 K and 1 0 1 .3 kPa.The entire sample is transferred to another container where the temperature is 283 K and the pressureis 94.6 kPa. In the space below, show a correct numerical setup for calculating the new volume ofthis sample of oxygen gas.

Classwork 6-8 & 6-9:

72

Base your answer to question 8 on the information below.

Air bags are an important safety feature in modem automobiles. An air bag is inflated in milliseconds by the explosive decomposition ofNaN3(s). The decomposition reaction produces Nz{g), as well as Na(s), according to the unbalanced equation below.

NaN3(s) � Na(s) + Nz{g)

8. When the air bag inflates, the nitrogen gas is at a pressure of 1 .30 atmospheres, a temperature of301 K, and has a volume of 40.0 liters. In the space below, calculate the volume ofthe nitrogen gasat STP. Your response must include both a correct numerical setup and the calculated volume.

Base your answer to question 9 using the information and diagrams below and your knowledge of chemistry.

Cylinder A contains 22.0 grams of C0z{g) and cylinder B contains Nz{g). The volumes, pressures,and temperatures of the two gases are indicated under each cylinder.

9. The temperature of the C0z{g) is increased to 450. K and the volume of cylinder A remains constant. In the space below, show a correct numerical setup for calculating the new pressure of the C0z{g) in cylinder A.

Cylinder A

V= 12.3L

P = 1.0 atm

T= 300. K

Cylinder B

V= 12.3L

P = 1.0 atm

T= 300. K

73

1 0. As the pressure of a given sample of a gas decreases at constant temperature, the volume of the gas

( 1 ) decreases (2) increases (3) remains the same 1 0

1 1 . A gas occupies a volume of 40.0 milliliters at 20oe. If the volume is increased to 80.0 milliliters at constant pressure, the resulting temperature will be equal to

80.0mL 80.0 mL ( 1 ) 200e x 40.0mL (3) 293 K x 40.0 mL

40.0mL 40 0mL (2) 200e x 80.0mL (4) 293 K x 80:0mL

1 1

12 . A gas occupies a volume of 444 mL at 273 K and 79.0 kPa. What is the finalkelvin temperature when the volume ofthe gas is changed to 1 ,880 mL and thepressure is changed to 38.7 kPa?

( 1 ) 3 1 .5 K(2) 292 K

(3) 566 K (4) 2,360 K

13 . A sample of gas occupies a volumeof 50.0 milliliters in a cylinder with

12

a movable piston. The pressure of thesample is 0.90 atmosphere and thetemperature is 298 K. What is thevolume ofthe sample at STP?

( 1 ) 4 1 mL(2) 49 mL

(3) 5 1 mL (4) 55 mL 1 3

14. A lightbulb contains argon gas at a temperature of 295 K and at a pressure of 75 kilopascals.The lightbulb is switched on, and after 30 minutes its temperature is 4 1 8 K.

In the space below, show a correct numerical setup for calculating the pressure of the gas inside thelightbulb at 4 1 8 K. Assume the volume of the lightbulb remains constant.

1 5. A sample of helium gas is in a closed system with a movable piston. The volume of the gas sample is changed when both the temperature and the pressure of Helium Gas in a Closed System the sample are increased. The table shows the initial temperature, pressure, and volume of the gas sample, as well as the final temperature and pressure of the sample.

Condition

initial

final

Temperature (K)

200. 300.

Pressure Volume (atm) (mL)

2.0 500. 7.0 ?

In the space below, show a correct numerical setup for calculating the final volume of the helium gas sample.

74

Base your answers to question 1 6 using the information below and your knowledge of chemistry.

A rigid cylinder is fitted with a movable piston. The cylinder contains a sample of helium gas, He(g), which has an initial volume of 1 25.0 milliliters and an initial pressure of 1 .0 atmosphere, as shown. The temperature of the helium gas sample is 20.0°e.

1 6. a) Express the initial volume of the helium gas sample in liters.

THandl.

M bl -1so.lmL--1

ova ""e_-' •• �.Ii piston -

Rigid cylinder

-100.0mL--7S.0mL--SO.OmL--2S.0mL-

Pressure gauge

b) The piston is pushed further into the cylinder. In the space below, show a correct numericalsetup for calculating the volume of the helium gas that is anticipated when the reading onthe pressure gauge is 1 .5 atmospheres. The temperature of the helium gas remains constant.

Base your answers to question 1 7 using the information below and your knowledge of chemistry.

A weather balloon has a volume of 52.5 liters at a temperature of 295 K. The balloon is released and rises to an altitude where the temperature is 252 K.

1 7. a) How does this temperature change affect the gas particle motion?

b) The original pressure at 295 K was 1 00.8 kPa and the pressure at the higher altitude at 252 Kis 45.6 kPa. Assume the balloon does not burst. In the space below, show a correct numericalsetup for calculating the volume of the balloon at the higher altitude.

18.

75

Unit 6 Practice Test

76

84

Unit Review: Physical Behavior of Matter

Place a checkmark next to each item that you can do! If a sample problem is given, complete it as evidence.

_____1. I can still do

everything from Unit 1.











_____7. I can define kinetic

energy, potential energy,

temperature, heat,

endothermic, and exothermic.

Defintions:

kinetic energy

potential energy

temperature

heat

endothermic

exothermic

____8. I can use particle

diagrams to show the

arrangement and spacing of

atoms/molecules in different

phases.

Draw a particle diagram to represent atoms of Li in each phase.

Solid Liquid Gas

85

_____9. I can compare solids,

liquids, and gases in terms of

their relative kinetic energy,

type of molecular motion,

ability to completely fill a

container, ability to change

shape.

Solid Liquid Gas

Relative

Kinetic

Energy

Type of

Molecular

Motion

vibrations, only vibration and

rotation

vibration,

rotation, and

translation

Ability to

Completely

Fill a

Container

Ability to

Change

Shape

_____10. I can state the change

of phase occurring in fusion,

solidification, condensation,

vaporization, melting, boiling,

sublimation, deposition, and

freezing.

During fusion a substance changes from ______________ to

______________.

During solidification a substance changes from ______________ to

______________.

During condensation a substance changes from ______________ to

______________.

During vaporization a substance changes from ______________ to

______________.

During melting a substance changes from ______________ to

______________.

During boiling a substance changes from ______________ to

______________.

During sublimation a substance changes from ______________ to

______________.

During deposition a substance changes from ______________ to

______________.

During freezing a substance changes from ______________ to

______________.

86

_____11. I can indicate if a

phase change is exothermic or

endothermic.

For each phase change listed, indicate whether the change is exothermic

or endothermic.

fusion/melting_______________________

solidification/freezing_______________________

condensation_______________________

vaporization/boiling_______________________

sublimation_______________________

deposition_______________________

_____12. Given a

heating/cooling curve, I can

determine the temperature at

which a substance

freezes/melts or

condenses/vaporizes. What is the freezing point of this substance?

What is the boiling point of this substance?

_____13. Given a


determine which sections of the

curve show changes in

potential energy.

On the graph, circle the sections that show a change in potential energy.

_____14. Given a


determine which sections of the

curve show changes in kinetic

energy.

On the graph, circle the sections that show a change in kinetic energy.

_____15. I can state the

temperature at which water

freezes in oC and K.

What is the freezing point of water in oC and K?

53oC

113oC

87



melts in oC and K.

What is the melting point of water in oC and K?



vaporizes/boils in oC and K.

What is the boiling point of water in oC and K?



condenses in oC and K.

What is the condensing point of water in oC and K?

_____19. I can use Reference

Table T to determine which

“heat” equation is needed for a

given problem.

Which heat equation should be used in each of the following:

a. How much heat is needed to vaporize 100.0 g of water at 100oC?

b. How much heat is needed to raise the temperature of 100.0 g of water by

35oC?

c. How much heat is needed to melt 100.0 g of ice at 0oC?

_____20. I can define specific

heat capacity, heat of fusion,

heat of vaporization.

Definitions:

specific heat capacity

heat of fusion

heat of vaporization

_____21. I can use the “heat”

equations to solve for any

variable, if I am given the

other variables.

How many grams of water can be heated by 15.0 oC using 13,500 J of heat?

It takes 5210 J of heat to melt 50.0 g of ethanol at its melting point. What is

the heat of fusion of ethanol?

88

_____22. I can state the 4 parts

of the Kinetic Molecular

Theory.

The four parts of the Kinetic Molecular Theory are:

a.

b.

c.

d.

_____23. I can define an ideal

gas.

Definition:

ideal gas


conditions of pressure and

temperature under which a gas

will act “ideally”.

A gas will act most “ideally” under the conditions of ___________ pressure

and ____________ temperature.

_____25. I can state the two

elements that act ideally most

of the time.

The two elements that act ideally most of the time are _____________ &

_______________.

_____26. I can explain how

pressure is created by a gas.

What causes gas molecules to create pressure?


relationship between pressure

and volume for gases

(assuming constant

temperature).

At constant temperature, as the pressure on a gas increases, the volume

____________________.


relationship between

temperature and volume for

gases (assuming constant

pressure).

At constant pressure, as the temperature on a gas increases, the volume

____________________.



temperature and pressure for

gases (assuming constant

volume).

In a fixed container (AKA “has constant volume), as the temperature on a

gas

increases, the pressure____________________.

89

_____30. I can state

Avogadro’s Hypothesis.

Avogadro’s Hypothesis

says_______________________________________

_____________________________________________________________

_

_____31. I can remember to

convert oC to K when using

the Combined Gas Law to

determine changes in V, P, or

T of a gas.

A gas originally occupies 2.3L at 56oC and 101.3 kPa. What will its

volume be at 100oC and 105.7 kPa?

_____32. I can define boiling

point and vapor pressure.

Definition:

boiling point

vapor pressure


condition of pressure that is

used for “normal” boiling

points.

The normal boiling point of a substance occurs at a pressure of

__________atm/_______________kPa.



atmospheric pressure and

boiling point.

As the atmospheric pressure increases, the boiling point

_________________.

unit 6: physical behavior of matter notes cw 6: physical behavior of matter notes & cw ... o the...

Documents