PhasesPhases & BehaviorBehavior of

MatterChs 13, 17,

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Phases and Behavior of Matter Goals

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a. Understand the effects motion of atoms and molecules in chemical and physical processes.

b. Compare and contrast atomic/molecular motion in

solids, liquids, gases, and plasmas.

c. Collect data and calculate the amount of heat given off or taken in by chemical or physical processes.

d. Analyzing (both conceptually and quantitatively) flow of energy during change of state (phase).

e. Apply concepts of the mole and Avogadro’s number to conceptualize and calculate molar volumes of gases.

Solid Liquid Gas

1)All matter is composed of small particles (atoms).

2)These particles are in constant motion.

3)These particles are colliding with each other and the walls of their container.

Kinetic Theory of Matter3 Clip

Kinetic Energy•Kinetic Energy is the energy of motion.

•Temperature is the measurement of the KE in an object.

•So, the more KE the higher the temp.

•As the particles in an object gain KE, the temperature goes up.

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Solids• Particles are closely packed

together.• Most are geometric. (called

Crystals)

5 Clip Amorphous Solids

• Particles are closely packed together.

• Most are geometric. (called Crystals)

• There are bonds between atoms/mol.

• Rigid shapes.• Definite shape.• Definite volume.

Amorphous Solids

•Amorphous solids are solids with random unoriented molecules

•Crystalline solids are arranged in fixed geometric patterns or lattices.

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• Lack highly ordered internal arrangement

• Melt over a temperature range

• Glass– Super-

cooled liquid

• Plastics• Some

scientist classify them as “thick liquids”

“without form”

Liquids• Particles in a liquid have more KE than

particles in a solid.• Liquid particles have enough KE to

overcome the forces that hold them together.

• The particles can now move past one another. (flow)

• Definite volume• No Definite shape.

Clip

Viscosity

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Viscosity• Resistance to flow

Gases• Gas particles have

more KE than liquid particles.

• They have enough energy to break all bonds and escape the liquid state.

• Particles are far apart- no attractice forces between them

8 Clip

Gases• Motion of the

molecules is random.• During collisions

between particles, KE is transferred without loss of total energy.

• No definite Shape• No definite Volume.

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Gases are compressible10

Plasmao Most common

state of matter in the universe

o Extremely high temperatures.

o Contains positively and negatively charged particles

11 Clip

Artificially produced plasmasArtificially produced plasmas

•Those found in plasma displays, including TVs

•Inside fluorescent lamps (low energy lighting), neon signs

•The electric arc in an arc lamp, an arc welder or plasma torch

•Plasma ball (sometimes called a plasma sphere or plasma globe)

Terrestrial plasmas

•Lightning

•The ionosphere

•The polar aurorae

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ReviewClip

o Force produced by high Force produced by high energy collisions strips energy collisions strips electrons from atoms.electrons from atoms.

o Sun, lighting bolts, neon Sun, lighting bolts, neon and fluorescent tubes, and fluorescent tubes, auroras.auroras.

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Gasses exert pressure on the walls of their containers and objects around

them.• Pressure- measure in

Pa• Atmospheric

pressure- collision of atoms and molecules in the air with object.-Standard pressure (atm) at 25˚C

• Barometer- measure atm pressure

• Conversions- Units of pressure

• (Q) What is 450kPA in mmHg and atm?– 4.4 atm

– 3.4 x 103 mm Hg

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Calculating molar volumes of gases

• The molar volume is the volume occupied by one mole of ideal gas at STP.

– Its value is: 22.414 L/mol..so 1 mol of any gas has a volume of 22.4 L… @

STP

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Goals: Apply concepts of the mole and Avogadro’s number to conceptualize and calculate molar volumes of gases

1 mol22.4 L

Standard Pressure = 1 atm

Standard Temperature = 0 deg C (273 K)

molar volumes of gasesPractice Problems

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2 H2 H22OO2 2 (l) ---> 2 H(l) ---> 2 H22O (g) + OO (g) + O2 2 (g)(g)

Decompose 1.1 g of HDecompose 1.1 g of H22OO22 in a flask with a volume of 2.50 L. in a flask with a volume of 2.50 L.

What is the volume of OWhat is the volume of O22 at STP? at STP?

Cool Fact: Bombardier beetle Cool Fact: Bombardier beetle uses decomposition of hydrogen uses decomposition of hydrogen peroxide to defend itself.peroxide to defend itself.

1.1 g1.1 g HH22OO22 1 mol H 1 mol H22OO22 1 mol O 1 mol O22 22.4 L O 22.4 L O22

34 g H34 g H22OO22 2 mol H 2 mol H22OO22 1 mol O 1 mol O22

= 0.36 L O2 at STP

molar volumes of gases1. What volume is occupied by 10 moles of

ammonia, NH3, at standard conditions?

2. What is the volume occupied by 40 grams of argon gas (Ar) at standard conditions?

3. What volume, in liters, is occupied by 1.5 x 1023 atoms of argon gas (Ar) at STP?

4. What volume would be occupied by 120 grams of argon gas (Ar) at standard conditions?

5. What volume will 0.750 moles of nitrogen gas occupy at STP?

6. How many moles are contained in 2.500 liters of methane (CH4) at STP?

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224 liters

22.4 liters

5.6 liters

67.2 liters

16.8 L N2

0.112 mol CH4

1. What mass of H2O is produced if 50.0% of CO2 is produced at STP?

2. How many moles of gas are present in 11.2 L at STP?

How many molecules?3. How many molecules of O2 are present in

56.0L at STP?56L 1 mol 6.022 x 1023 molecules = 22.4 L 1 mol

4. A sample of carbon dioxide gas (CO2) contains 6 x 1022 molecules. How many moles of carbon dioxide does this represent?

1/10 mole

C3H8 (g) + 5 O2 (g) 3 CO2 (g) + 4 H2O (g)19

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Measuring Heat• Heat is a form of energy, and it is

measure in Joules or Calories.• Calorie; the quanity of heat needs

to raise the temperature of 1g of pure water 1˚C.

• Note: Dietary Calorie is actually 1kcal.

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Specific HeatSpecific Heat•Adding Energy to a

material Causes the…–Temperature to go up.

•Taking energy away from a substance causes the temp. to…–Go down!

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Which would heat up faster? The aluminum or

the plastic?

Specific means Specific means “certain”“certain”

•Have you ever noticed that on a hot summer day the pool is cooler than the hot cement?

•OR maybe that the ocean is cooler than the hot sand?

•Why? The sun has been beating down on (delivering energy to) both of them for the same amount of time.....same amount of energy.

• It takes more thermal energy to raise the temperature of water that it does the cement! 24

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Specific HeatSpecific Heat•The amount of energy required to raise the temperature of a material (substance).

•It takes different amts of energy to make the same temp change in different substances.

•We call the amt required: Specific Heat!

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Every materials requires a different amount of energy to change its temperature.

Note: The lower the number, the FASTER the material heats up….and cools down

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Cp Stands for “Heat Capacity”

(Cp )

Specific Heat of Specific Heat of waterwater

•The Cp is high because H2O mols. form strong bonds w/each other.

•It takes a lot of energy to break the bonds so that the the molecules can then start to move around faster (HEAT UP).

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Calculating Amount of Calculating Amount of HeatHeat

The Greek letter Δ means “change The Greek letter Δ means “change in”in”

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p

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EXAMPLE :• What amount of heat is required to raise the

temperature of 85.9 kg of water by 7C? The specific heat of water is 4.184 J/gC.

• Mass = 85.9kg• Q = ?• Δt = 7°• Cp = 4.184 J/g-C?• Q =m x Cp x Δt• Q= (85.9kg)(4.184 J/g-C)(7°C)• Q= 2515.8 J• (WHAT DOES THAT MEAN?)

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Can you get a negative “Q”

• Q =m x Cp x Δt

• Yes.

• If the object is LOSING heat.

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Specific Heat Practice with a friend….

1. How much heat must be absorbed by 375 grams of water to raise its temperature by 25° C?

2. How much energy (in calories and in Joules) will it take to raise the temperature of 75.0 g of water from 20.0 to 55.0 oC?

3. What is the heat in Joules required to raise the temperature of 25 grams of water from 0 °C to 100 °C? What is the heat in calories?

4. It takes 487.5 J to heat 25 grams of copper from 25 °C to 75 °C. What is the specific heat in Joules/g·°C?

5. 350 J are released as ice ( Specific Heat = 2.1 J / (g oC) ) cools from - 5.0 oC to -32 oC. What is the mass of ice?

2630 cal and 1.1 x 10 4 J

6.2 g

10450 J or 2500 calories

0.39 J/g·°C.

3.9 x 104 J

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Changing State35

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Sublimation• Some substances go from the solid state directly to the

gaseous state. This happens when a substance was below it freezing point and is suddenly moved to a location where it is above its boiling point

• EX: CO2

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Boiling Point and Pressure

• Water boils at about 95 degrees C in Denver and higher than 100 degrees C in a pressure cooker.

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•It takes energy to cause phase It takes energy to cause phase changes( soild-liq-gas)changes( soild-liq-gas)

•Removal of energy (gas-liq-solid)Removal of energy (gas-liq-solid)

Phase changes do notdo not change the substance

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Clip

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• The amount of energy required for a substance to go from a solid to a liquid is

called the

HEAT OF FUSION.• (EX) it takes 334,000

Joules of energy to melt 1 kg of ice. No temperature change.

0°C 0°CNO TEMP CHANGE

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• The amount of energy required to change a liquid to a gas is called the……Heat of VaporizationHeat of Vaporization

• EX: It takes 2,260,000 Joules of energy to vaporize 1 kg of water.

100 °C 100 °CNO TEMP CHANGE

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Practice Problems

1. What is the heat in Joules required to convert 25 grams of water into steam? What is the heat in calories?

2. What is the heat in Joules required to melt 25 grams of ice? What is the heat in calories?

3. How much energy would be required to melt 15.0 g of ice at 0 oC?

4. How much energy would it take to boil 36.0 g of water at 100 oC?

5.01 KJ

81.4 KJ

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8350 Joules or 2000 cal

56425 J, 13,500 cal

Information: H20Heat of Fusion (hf) = 334 J/gHeat of vaporization (hv) =2260 J/g

Combination Problems….You can do this

• How much energy would it take to melt 30.0 g of ice at 0 oC and warm the resulting liquid to 35.0 oC? – 14.4 KJ

• How much energy would it take to warm 30.0 g of water at 35 oC to the boiling point and boil all the liquid away? – 76 KJ

• How much energy would be reqired to melt 10.0 g of ice at 0 oC, warm the resulting liquid to 100 oC, and change it to steam at 100 oC? – 30.1 KJ

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• The triple point of a substance is the temp. and pressure at which the three phases of that substance coexist

• Phase depends not only on temp. but also pressure.

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• Phase depends not only on temp. but also pressure.

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Thermal ExpansionThermal Expansion•When objects are When objects are

heated, they heated, they expandexpand..•When they are cooled, When they are cooled,

they they contractcontract..• Video Clip

When heat is added to most materials they expand.48

Thermal Thermal ExpansionExpansion

Typical expansion joints on a steel span

bridge.

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• Thermometers: Work because of thermal expansion.

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Pressure (Pa)= Force (N)Area (M2)

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Gases exert pressure on their container

TheThe PascalPascal (Pa) is the (Pa) is the SI unit of pressureSI unit of pressure

• Pressure: The amt of The amt of force exerted force exerted per unitper unit of of areaarea.

• Gases exert pressure by colliding with “things.”

1.Other particles of gas2.Sides of the container3.Objects within the area of

the gas, like you. 

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Clip

Boyle’s and Charles’ Law

• Both deal with gases.

• Boyle’s LawBoyle’s Law– As the volume

decreases, the pressure increases.

• Charles’ LawCharles’ Law– As the temperature

decrease, the volume of a gas decreases.

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Boyle’s Law• Relationship between volume and pressure.

P1V1 = P2V2

You tubeClip

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Boyle’s Law P1V1 = P2V2

If you If you decreasdecrease the e the volumevolume, the , the pressurpressure will e will increasincrease ( no e ( no ΔΔt)t)

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Charles’ Law• Relationship between volume and temperature.

In theory there is a temperature in which gases ceases to have

volume.

This temp. is referred to as absolute zero.

Absolute Temp. ScaleT (K) = °C + 273.15 K

                                      

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Charles’ LawIf you increase the temperature,

the volume will increase

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Joseph Louis Gay-Joseph Louis Gay-Lussac (1778-1850)Lussac (1778-1850)

If n and V are constant, If n and V are constant, then P then P αα T T

P and T are directly P and T are directly proportional. proportional.

• If one temperature If one temperature goes up, the pressure goes up, the pressure goes up!goes up!

Gay-Lussac’s LawGay-Lussac’s Law

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• PHET Gas Properties simulation

• PHET States of Matter simulation

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The End

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