The Temperature-Pressure Relationship Gay-Lussac’s Law  The pressure of a gas is directly proportional to the temperature of a gas  Temperature goes up; pressure goes up P 1 = P 2 T 1 T 2  The pressure of a gas is directly proportional to the temperature of a gas  Temperature goes up; pressure goes up P 1 = P 2 T 1 T 2

Gay-Lussac’s Law example problems  The gas left in a used aerosol can is at a pressure of 103 kPa at 25 o C. If the can is thrown into a fire, what is the pressure of the gas when it reaches 928 o C? 103 kPa = P K 1201 K P 2 = 415 kPa  The gas left in a used aerosol can is at a pressure of 103 kPa at 25 o C. If the can is thrown into a fire, what is the pressure of the gas when it reaches 928 o C? 103 kPa = P K 1201 K P 2 = 415 kPa

Gay-Lussac’s Law example problems  Your turn  A container of propane has a pressure of kPa at a morning temperature 15 o C. By mid afternoon the temperature has reached 32 o C. What is the pressure inside the propane tank?  Your turn  A container of propane has a pressure of kPa at a morning temperature 15 o C. By mid afternoon the temperature has reached 32 o C. What is the pressure inside the propane tank?

Gay-Lussac’s Law example problems  Answer kPa = P K305 K P 2 = 115 kPa  Answer kPa = P K305 K P 2 = 115 kPa

The combined gas law P 1 x V 1 = P 2 x V 2 T 1 T 2 P 1 x V 1 = P 2 x V 2 T 1 T 2

The combined gas law example problem  The volume of a gas-filled balloon is 30.0 L at 40 o C and 153 kPa. What volume will the balloon have at STP? 153 kPa x 30.0 L = kPa x V V 2 = 3.95 L  The volume of a gas-filled balloon is 30.0 L at 40 o C and 153 kPa. What volume will the balloon have at STP? 153 kPa x 30.0 L = kPa x V V 2 = 3.95 L

The combined gas law example problem  Your turn  A gas-filled balloon is 25.0 L at 35 o C and 145 kPa. What is the temperature if the volume increases to 28 L and a pressure of 152 kPa?  Your turn  A gas-filled balloon is 25.0 L at 35 o C and 145 kPa. What is the temperature if the volume increases to 28 L and a pressure of 152 kPa?

The combined gas law example problem  Answer 145 kPa x 25.0 L = 152 kPa x 28 L 308 K T 2 T 2 = 362 K = 88.6 o C  Answer 145 kPa x 25.0 L = 152 kPa x 28 L 308 K T 2 T 2 = 362 K = 88.6 o C