The Gas Laws Prentice-Hall Chapter 14.2 Dr. Yager

Objectives  Describe the relationships among the temperature, pressure, and volume of a gas  Use the combined gas laws to solve problems

The Four Laws  Boyle’s: Pressure and Volume  Charles’s: Temperature and Volume  Gay-Lussac’s: Pressure and Temperature  The Combined Gas Law: Pressure, Volume, and Temperature.

All Four Laws are Derived from the Ideal Gas Law

Boyle’s Law: Pressure and Volume Boyle’s Law: Pressure and Volume states that for a gas with constant temperature and number of moles, the volume of the gas varies inversely with pressure. Boyle’s Law

A gas with a volume of 4.00 L at a pressure of 205 kPa is allowed to expand to a volume of 12.0 L. What is the pressure in the container if the temperature remains constant? P 1 x V 1 = P 2 x V 2 P 1 = 205 kPa V 1 = 4.00 L P 2 = ? V 2 = 12.0 L 205kPa x 4.00L = P 2 x 12.0L P 2 = kPa

Charles’s Law: Temperature and Volume As the temperature of an enclosed gas increases, the volume increases, if the pressure and number of moles are constant. Charles’s Law

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

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

Exactly 5.00 L of air at o C is warmed to o C. What is the new volume if the pressure remains constant? V 1 = 5.00 L, T 1 = o C V 2 = ? L, T 2 = 100 o C

Gay-Lussac’s Law: Pressure and Temperature As the temperature of an enclosed gas increases, the pressure increases, if the volume and number of moles are constant. Gay-Lussac’s Law

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

Gay-Lussac’s Law states that the pressure of a gas is directly proportional to the Kelvin temperature if the volume and number of moles remain constant.

The pressure in a car tire is 198 kPa at 27 o C. After a long drive, the pressure is 225 kPa. What is the temperature of the air in the tire? Assume the volume is constant. P 1 = 198 kPa T 1 = 27 o C P 2 = 225 kPa T 2 = ?

The combined gas law describes the relationship among the pressure, temperature, and volume of an enclosed gas for a constant number of moles. Combined Gas Law

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

A 5.00 L air sample has a pressure of 107 kPa at a temperature of o C. If the temperature is raised to 102 o C and the volume expands to 7.00 L, what will the new pressure be? P 1 = 107 kPa, V 1 = 5.00L, T 1 = o C P 2 = ? kPa, V 2 = 7.00L, T 2 = 102 o C P 2 = kPa

1. If the volume of a gas in a container was reduced to one fifth the original volume at constant temperature, the pressure of the gas in the new volume would be a.one and one fifth times the original pressure. b.one fifth of the original pressure. c.four fifths of the original pressure. d.five times the original pressure.

1. If the volume of a gas in a container was reduced to one fifth the original volume at constant temperature, the pressure of the gas in the new volume would be a.one and one fifth times the original pressure. b.one fifth of the original pressure. c.four fifths of the original pressure. d.five times the original pressure.

2. A balloon appears slightly smaller when it is moved from the mountains to the seashore at constant temperature. The best gas law to explain this observation would be a.Gay-Lussacs's Law. b.Graham's Law. c.Boyle's Law. d.Charles's Law.

2. A balloon appears slightly smaller when it is moved from the mountains to the seashore at constant temperature. The best gas law to explain this observation would be a.Gay-Lussacs's Law. b.Graham's Law. c.Boyle's Law. d.Charles's Law.

3. At 46°C and 89 kPa pressure, a gas occupies a volume of L. How many liters will it occupy at 0°C and 20.8 kPa? a L b.2.58 L c L d.2.20 L

3. At 46°C and 89 kPa pressure, a gas occupies a volume of L. How many liters will it occupy at 0°C and 20.8 kPa? a L b.2.58 L c L d.2.20 L