Download - KINETIC MOLECULAR THEORY
![Page 1: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/1.jpg)
KINETICMOLECULAR
THEORY
![Page 2: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/2.jpg)
Physical Properties of Gases:• Gases have mass• Gases are easily compressed• Gases completely fill their containers (expandability) •Gases diffuse rapidly •Gases exert pressure
![Page 3: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/3.jpg)
Kinetic Molecular Theory
A theory that explains the physical properties of gases by describing
the behavior of the particles
![Page 4: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/4.jpg)
KMT has 5postulates:
![Page 5: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/5.jpg)
#1A gas consists of very small particles that
have mass. (molecules or atoms)
![Page 6: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/6.jpg)
#2Gas particles are
very far apart from each other.
(therefore gases are easily compressed)
![Page 7: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/7.jpg)
#3
Gas particles are in continuous, rapid, random motion.
![Page 8: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/8.jpg)
#4Collisions of gas
particles (with each other and with container) are perfectly elastic(no energy lost)
![Page 9: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/9.jpg)
#5The average energy of the gas particles
depends on the temperature of the
gas.
![Page 10: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/10.jpg)
Measuring gases
• Experimental work in chemistry requires measurements of quantities . Like volume, temperature, pressure and amount. This quantities are variables.
![Page 11: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/11.jpg)
We can measure gases in 4 ways:Measurement Unit
Amount of gas Moles
Volume (V) Liters (L)
Temperature (T) °C, °F, or K
Pressure (P) atm, kPa, Torr, mm Hg, or lb/in2
![Page 12: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/12.jpg)
Temperature (T)
A measurement of the average kinetic energy of a substance, the temperature is related with speed of the molecules of the gas.
![Page 13: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/13.jpg)
Higher temperatures cause gas particles to move faster
![Page 14: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/14.jpg)
K = °C + 273
14°C = ? K14°C + 273 = 287K
To solve gas problems, the temp must always be
in Kelvin (K) !!!
![Page 15: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/15.jpg)
Pressure (P)
The force per unit area on a
surface
![Page 16: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/16.jpg)
Pressure is caused by gas particles slamming into the container’s walls.
![Page 17: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/17.jpg)
•When pressure increases, the number of collisions in a determine time increases
also
![Page 18: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/18.jpg)
VOLUME (V)
• The volume of the gas is the same as the volume of the container. The unit is the Liter (L) = 1000cm3
![Page 19: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/19.jpg)
Units of Pressure:1) atmosphere (atm) 2) Pascal (Pa) 3) millimeters of Mercury (mm Hg)4) Torr5) Pounds per square inch (lb/in2)
1 atm = 101,325 Pa 1 atm= 760 mm Hg = 760 torr
1 atm = 14.70 lb/in2
Bar = 100,000 Pa = 0.9869
![Page 20: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/20.jpg)
Amount of gas
• The mole is the unit for specifying the amount of a sample of matter. You can
relate the number of moles and the mass to the number of
gas particles.
![Page 21: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/21.jpg)
• The pressure exerted by air in the atmosphere is called atmospheric pressure.•VIDEO 1 Weather and air pr
essure•VIDEO 2 What is weather?
![Page 22: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/22.jpg)
Learning CheckA. What is 475 mm Hg expressed in atm? 1) 475 atm 2) 0.625 atm 3) 3.61 x 105 atm
B. The pressure of a tire is measured as 29.4 psi. What is this pressure in mm Hg?
1) 2.00 mm Hg2) 1520 mm Hg3) 22,300 mm Hg
![Page 23: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/23.jpg)
SolutionA. What is 475 mm Hg expressed in atm?
485 mm Hg x 1 atm = 0.625 atm (B) 760 mm Hg
B. The pressure of a tire is measured as 29.4 psi. What is this pressure in mm Hg?29.4 psi x 1.00 atm x 760 mmHg = 1.52 x 103 mmHg 14.7 psi 1.00 atm (B)
![Page 24: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/24.jpg)
Enclosed Gases
• If the container is closed, the pressure inside the container may be different from the atmospheric pressure.• Manometer: Instrument to
measure the pressure in a closed container.
![Page 25: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/25.jpg)
![Page 26: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/26.jpg)
• Determining the pressure in the container will depend on the levels of the Hg on the two sides.• Pressure of the gas in the container is
the same as the atmosphere WHEN THE TWO LEVELS ARE EQUALY HIGH• If the level of mercury is LOWER on the
container side, the pressure in the container is higher than atmosphere.
![Page 27: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/27.jpg)
• The difference between pressures in mmHg is simply the difference between the heights of the two columns.• To find the pressure of the gas in the
container you must add or subtract the difference in pressures to the atmospheric pressure, witch you have separately determined by using a barometer.
![Page 28: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/28.jpg)
• If the mercury level in the container is HIGHER that atmospheric side, the pressure in the container is less than the atmospheric pressure.
![Page 29: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/29.jpg)
• WHEN THE GAS PRESSURE IS HIGHER THAN ATMOSPHERE PRESSURE, THE LEVEL OF MERCURY ON THE SIDE OF THE GAS WILL BE LOWER THAN OPEN ENDED SIDE.
Add differences
• WHEN GAS PRESSURE IS LOWER THAN ATMOSPHERIC PRESSURE, THE LEVEL ON THE SIDE OF THE GAS WILL BE HIGHER THAN OPEN ENDED SIDE..
• Subtract differences
![Page 30: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/30.jpg)
• Pcontainer = Height difference – Atmospheric pressure
• Pcontainer = Height difference + Atmospheric pressure
![Page 31: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/31.jpg)
STOP…collaborate and listen
![Page 32: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/32.jpg)
THE GAS LAWS
• Mathematical representation of the observed relationships among the 4 variables
• BOYLE’S LAW : The pressure- volume Famous experiment involved trapping air,
changing its pressure , and measuring its volume.
If the temperature remains unchanged the product of the pressure times the volume have a constant value K.
![Page 33: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/33.jpg)
• PV = K• The pressure and volume of a sample of gas at
constant temperature are inversely proportional to each other.
• IF PRESSURE INCREASES, VOLUME DECREASES
• IF VOLUME INCREASES, PRESSURE DECREASES
• At same temperature the product of the pressure times the volume of a sample is always the same.
![Page 34: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/34.jpg)
Boyle’s Law
MUST BE AT CONSTANT TEMPERATURE!!
P1V1 = P2V21 = trial 1
2 = after (trial 2)
![Page 35: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/35.jpg)
A gas occupies a volume of 0.458 L at a pressure of 1.01 kPa and temperature of 295 Kelvin. Although the temperature
stays the same, the volume is increased to 0.477 L. What is the new pressure?
0.970 kPa
![Page 36: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/36.jpg)
Charles’ Law
• The relationship between volume gas and its temperature while the pressure and the amount of gas were held constant
• VOLUME INCREASES AS TEMPERATURE INCREASES
• V= K2 T• At constant pressure the volume of a fixed
amount of gas is directly proportional to its absolute temperature.
![Page 37: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/37.jpg)
Charles’ Law
MUST BE AT CONSTANT PRESSURE!!
V1T2 = V2T1
1 = before2 = after
![Page 38: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/38.jpg)
What will be the volume of a gas sample at 309 K if its volume at 215 K is 3.42 L? Assume that pressure is constant.
4.92 L
![Page 39: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/39.jpg)
Gay-Lussac’s Law
MUST BE AT CONSTANT VOLUME!!
1 = before2 = after
2
2
1
1
T
P
T
P
![Page 40: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/40.jpg)
A balloon with a pressure of 0.900 atm is heated from
105 K to 155 K. If volume is held constant, what is the new pressure?
1.33 atm
![Page 41: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/41.jpg)
Combined Gas Law
1 = before 2 = after2
22
1
11
T
VP
T
VP
JUST HOLD ONE QUANTITY CONSTANT!!(take it out of the equation)
![Page 42: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/42.jpg)
The gas in a 0.010 L container has a pressure of 1.39 atmospheres. When the gas is transferred to a 0.017 L container at the same
temperature, what is the pressure of the gas?
0.82 atm
![Page 43: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/43.jpg)
The gas inside a 70.8 mL piston has a temperature of 35.0°C. If the temperature is raised to 100.0°C, what is the new volume of the gas?
85.7 mL
![Page 44: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/44.jpg)
An elastic container is inflated to a volume of 18.0 liters at a pressure of 1.26 atm. The container then expands to a new volume at a pressure of
1.05 atm. What is the new volume?
21.6 liters
![Page 45: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/45.jpg)
Avogadro’s Law
The amount- volume relationship
Equal volumes of gas (at same P and T) contain the same amount of particles
![Page 46: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/46.jpg)
• It states that all gases show the same physical behavior
• A gas with a larger volume must consist of a greater number of particles. As long as the pressure and temperature do not change
• If the amount of gas increases the volume increases
• If the amount of gas decreases the volume decreases
![Page 47: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/47.jpg)
1 mole = 6.02 x 1023 particles
Only works at same P and T
V = K n
1 mole = 22.4 L
![Page 48: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/48.jpg)
Ideal Gas LawThe mother of all gas
laws. It includes everything!
PV = nRT
![Page 49: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/49.jpg)
P = pressure (atm)V = volume (L)n = moles (mol)
R = Gas ConstantT = Temperature
(Kelvin)
PV = nRT
![Page 50: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/50.jpg)
KmolLatm0821.0R
MUST USE THESE UNITS!!!
PV = nRT
![Page 51: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/51.jpg)
If the pressure exerted by a gas at 0.00°C in a volume of 0.0010 L is 5.00 atm, how many moles of gas are present?
2.2 x 10-4 moles
![Page 52: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/52.jpg)
Ideal gases don’t really exist…
…real gases do!
![Page 53: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/53.jpg)
Ideal Gas
A gas that is described by the KMT postulates.
Ideal Gas Law works most of the time.
![Page 54: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/54.jpg)
It does NOT work at very low temperatures and very high pressures.
![Page 55: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/55.jpg)
Dalton’s Law of Partial Pressures
The sum of the partial pressures
of the gases is equal to the total
pressure
![Page 56: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/56.jpg)
Dalton’s Law of Partial Pressures
Ptotal = P1 + P2 + P3 + …
![Page 57: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/57.jpg)
A balloon contains O2 and N2 gas. If the partial pressure of the O2 is 0.75 atm and the partial pressure of the N2 is 0.55 atm, what is the total pressure of
the balloon?
1.30 atm
![Page 58: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/58.jpg)
The gas inside a 70.8 mL can contains H2O(g) and CO2(g) and has a total pressure of 760 mm Hg. If the partial pressure of the H2O is 350 mm Hg, what is the partial
pressure of the CO2?
410 mm Hg
![Page 59: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/59.jpg)
STPStandard Temperature and PressureBehavior of gases depend strongly on temperature and pressure .
0°C or 273 K and 1 atm
![Page 60: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/60.jpg)
How many moles of N2 gas are in a 4.5 L balloon at STP?
0.20 moles
![Page 61: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/61.jpg)
A gas at STP is heated to 55°C. What is the new pressure if volume is held constant?
1.2 atm
![Page 62: KINETIC MOLECULAR THEORY](https://reader036.vdocuments.net/reader036/viewer/2022062518/56814385550346895db002bb/html5/thumbnails/62.jpg)
A gas tank contains CO2 and O2 gas. What is the total pressure in the tank if the partial pressure of CO2 is 0.45 atm and the partial pressure of O2 is 0.55?
1.00 atm