Chemistry 14.2Chemistry 14.2

The Gas LawsThe Gas Laws• This hot air balloon was This hot air balloon was

designed to carry a designed to carry a passenger around the passenger around the world. You will study world. You will study some laws that will some laws that will allow you to predict gas allow you to predict gas behavior under specific behavior under specific conditions, such as in a conditions, such as in a hot air balloon.hot air balloon.

Boyle’s Law: Pressure and Boyle’s Law: Pressure and VolumeVolume

Boyle’s Law: Pressure and VolumeBoyle’s Law: Pressure and Volume

How are the pressure, volume, How are the pressure, volume, and temperature of a gas and temperature of a gas related?related?

Boyle’s Law: Pressure and Boyle’s Law: Pressure and VolumeVolume

If the temperature is constant, If the temperature is constant, as the pressure of a gas as the pressure of a gas

increases, the volume increases, the volume decreasesdecreases..

Boyle’s Law: Pressure and Boyle’s Law: Pressure and VolumeVolume

Boyle’s lawBoyle’s law states that for a states that for a given mass of gas at constant given mass of gas at constant temperature, the volume of the temperature, the volume of the gas varies inversely with gas varies inversely with pressure.pressure.

Boyle’s Law: Pressure and Boyle’s Law: Pressure and VolumeVolume

Boyle’s Law: Pressure and Boyle’s Law: Pressure and VolumeVolume Simulation 15Simulation 15

Examine the relationship between gas, Examine the relationship between gas, volume and pressure.volume and pressure.

14.114.1

14.114.1

14.114.1

14.114.1

for Sample Problem 14.1for Sample Problem 14.1

Sample Problem SolutionSample Problem Solution

205 kPa X 4.00L = P205 kPa X 4.00L = P22 X 12.0 L X 12.0 L

PP2 2 = 205 kPA X = 205 kPA X 4.00L 4.00L = 68.3 kPa= 68.3 kPa 12.0L12.0L

Charles’s Law: Temperature Charles’s Law: Temperature and Volumeand Volume

Charles’s Law: Temperature and Charles’s Law: Temperature and VolumeVolume

As the temperature of an As the temperature of an enclosed gas increases, the enclosed gas increases, the volume increases, if the volume increases, if the pressure is constant.pressure is constant.

Charles’s Law: Temperature Charles’s Law: Temperature and Volumeand Volume

As the temperature of the water As the temperature of the water increases, the volume of the balloon increases, the volume of the balloon increases.increases.

Charles’s Law: Temperature Charles’s Law: Temperature and Volumeand Volume

Charles’s lawCharles’s law states that states that the volume of a fixed mass of the volume of a fixed mass of gas is directly proportional to gas is directly proportional to its Kelvin temperature if the its Kelvin temperature if the pressure is kept constant.pressure is kept constant.

Charles’s Law: Temperature Charles’s Law: Temperature and Volumeand Volume

Charles’s Law: Temperature Charles’s Law: Temperature and Volumeand Volume

Simulation 16Simulation 16 Examine the relationship between gas Examine the relationship between gas

volume and temperature.volume and temperature.

14.214.2

14.214.2

14.214.2

14.214.2

for Sample Problem 14.2for Sample Problem 14.2

Gay-Lussac’s Law: Pressure Gay-Lussac’s Law: Pressure and Temperatureand Temperature

Gay-Lussac’s LawGay-Lussac’s Law: : Pressure and Pressure and TemperatureTemperature

As the temperature of an enclosed As the temperature of an enclosed gas increases, the pressure gas increases, the pressure increases, if the volume is increases, if the volume is constant.constant.

Gay-Lussac’s Law: Pressure Gay-Lussac’s Law: Pressure and Temperatureand Temperature

When a gas is heated at constant When a gas is heated at constant volume, the pressure increases.volume, the pressure increases.

Gay-Lussac’s Law: Pressure Gay-Lussac’s Law: Pressure and Temperatureand Temperature

Gay-Lussac’s lawGay-Lussac’s law states that the states that the pressure of a gas is directly pressure of a gas is directly proportional to the Kelvin proportional to the Kelvin temperature if the volume temperature if the volume remains constant.remains constant.

Gay-Lussac’s Law: Pressure Gay-Lussac’s Law: Pressure and Temperatureand Temperature

A pressure cooker A pressure cooker demonstrates Gay-Lussac’s demonstrates Gay-Lussac’s Law.Law.

Gay-Lussac’s Law: Pressure Gay-Lussac’s Law: Pressure and Temperatureand Temperature

Simulation 17Simulation 17 Examine the relationship between gas Examine the relationship between gas

pressure and temperature.pressure and temperature.

14.314.3

14.314.3

14.314.3

14.314.3

for Sample Problem 14.3for Sample Problem 14.3

The Combined Gas LawThe Combined Gas Law

The Combined Gas LawThe Combined Gas Law When is the combined gas law When is the combined gas law

used to solve problems?used to solve problems?

The Combined Gas LawThe Combined Gas Law

The The combined gas lawcombined gas law describes the relationship describes the relationship among the pressure, among the pressure, temperature, and volume of temperature, and volume of an enclosed gas.an enclosed gas.

The Combined Gas LawThe Combined Gas Law

The combined gas law allows you The combined gas law allows you to do calculations for situations in to do calculations for situations in which only the amount of gas is which only the amount of gas is constant.constant.

14.414.4

14.414.4

14.414.4

14.414.4

for Sample Problem 14.4for Sample Problem 14.4

Problem Solving 14.14Problem Solving 14.14 Solve Problem 14 with the help Solve Problem 14 with the help

of an interactive guided tutorial.of an interactive guided tutorial.

The Combined Gas LawThe Combined Gas Law Weather balloons Weather balloons

carry data-carry data-gathering gathering instruments high instruments high into Earth’s into Earth’s atmosphere. At atmosphere. At an altitude of an altitude of about 27,000 about 27,000 meters, the meters, the balloon bursts.balloon bursts.

14.2 Section Quiz.14.2 Section Quiz.

14.2.14.2.

14.2 Section Quiz.14.2 Section Quiz.

1. If the volume of a gas in a container 1. If the volume of a gas in a container were reduced to one fifth the original were reduced to one fifth the original volume at constant temperature, the volume at constant temperature, the pressure of the gas in the new volume pressure of the gas in the new volume would be would be

one and one fifth times the original pressure.one and one fifth times the original pressure.

one fifth of the original pressure.one fifth of the original pressure. four fifths of the original pressure.four fifths of the original pressure. five times the original pressure.five times the original pressure.

14.2 Section Quiz.14.2 Section Quiz.

2. A balloon appears slightly smaller 2. A balloon appears slightly smaller when it is moved from the mountains when it is moved from the mountains to the seashore at constant to the seashore at constant temperature. The best gas law to temperature. The best gas law to explain this observation would be explain this observation would be

Gay-Lussacs's Law.Gay-Lussacs's Law. Graham's Law.Graham's Law. Boyle's Law.Boyle's Law. Charles's Law.Charles's Law.

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