Unit 7. Gas Properties Kinetic Molecular Theory Review Ideal Gases are perfect gases. They have: No...

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GASES Unit 7

Transcript of Unit 7. Gas Properties Kinetic Molecular Theory Review Ideal Gases are perfect gases. They have: No...

Page 1: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

GASESUnit 7

Page 2: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Video 7.1Gas Properties

Page 3: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Kinetic Molecular Theory Review

Ideal Gases are perfect gases. They have:No massNo volumeNo attractive forces

When will real gases behave this way?When they are spread outTemperature is highPressure is low

Page 4: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Boyle’s Law Pressure and volume have

an indirect relationship.

P1V1=P2V2

What happens to a balloon if you put pressure on it? If you release it into the atmosphere?

Page 5: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.
Page 6: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.
Page 7: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Charles’ Law

Volume and temperature have a direct relationship.

V1/T1 = V2/T2

What happens to a car tire in the winter?

Page 8: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.
Page 9: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Gay-Lussac’s Law

Pressure and temperature have a direct relationship.

P1/T1 = P2/T2

Page 10: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Video 7.2Combined Gas Law

Page 11: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Combined Gas Law

P1V1 = P2V2 T1 T2

Only used when discussing initial and final conditions of a gas.

If something is held constant, cross it out of the equation.

Temperature must be in Kelvin!

Page 12: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Question 1

P1V1 = P2V2 T1 T2

P1V1 = P2V2

(5.6x103)(1.53) = (1.5x104)(x)

X = .571 L

Page 13: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Question 2 A 32.9L sample of a gas at constant

pressure increases in temperature from 25 to 45C. Should the volume increase or decrease? Calculate the new volume.

P1V1 = P2V2 T1 T2

V1 = V2T1 T2

32.9 = x . 298 318 X= 35.1 L

Page 14: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Question 3

A gas in a rigid container has a pressure of 3.5 atmospheres at 200K. Calculate the pressure at 273K.

P1V1 = P2V2 T1 T2

P1 = P2 T1 T2

3.5 = x .200 273

X = 4.78 atm

Page 15: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Video 7.3Other Gas Laws

Page 16: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Avogadro’s Law

Two different gases as the same temperature, volume, and pressure have the same number of molecules.

Page 17: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Graham’s Law of diffusion

Gases move from high to low concentrations. Lighter gases diffuse faster.

Which diffuses the fastest: He or N2?

Why will F2 and Ar diffuse at almost the same rate?

Page 18: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Graham’s Law of diffusion

Page 19: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Dalton’s Law of partial pressures The total pressure in a system of gases

equals the pressure of each individual gas combined.

Page 20: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Example

1. If the total pressure of a container of gases is 3 atmospheres and it contains 1 atmosphere of oxygen, 0.5 atm of nitrogen, 0.75 atm of methane, what is the partial pressure of the remaining gas?

3 – 1 - .5 - .75 = .75 atm

Page 21: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Harder Example

2. A mixture of gases contain 4.46 moles Ne, 0.74 moles of Ar, and 2.15 moles of Xe. Calculate the partial pressure of each gas if the total pressure is 2 atm.

PNe= (4.46/7.35)(2) = 1.21 atmPAr= (0.74/7.35)(2) = 0.201 atmPxe= (2.15/7.35)(2) = 0.585 atm

Page 22: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Class Notes

Page 23: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

How do we breathe?

Page 24: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Why is Boyle’s law important to scuba divers?

Page 25: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

Why is Charles’ Law important in hot air ballooning?

Page 26: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.
Page 27: Unit 7. Gas Properties Kinetic Molecular Theory Review  Ideal Gases are perfect gases. They have: No mass No volume No attractive forces  When will.

The general-purpose tank car in the photo before was being steam cleaned in preparation for maintenance.  The job was still in progress at the end of the shift so the employee cleaning the car decided to block in the steam.  The car had no vacuum relief so as it cooled, the steam condensed and the car imploded.