Gay-Lussac’s Law

As temperature increases, in a rigid container with constant volume, the average speed of the gas molecules increases, creating more collisions with the walls of the container, and as a result the gas pressure increases.

Gay-Lussac’s Law Pressure of a fixed amount of gas, at constant volume, is directly proportional to its Kelvin temperature P i P f T i T f =

Graphically

A cylinder of chlorine gas is stored in a concrete- lined room for safety. The cylinder is designed to withstand 50 atm of pressure. The pressure gauge reads 35.0 atm at 23.2°C. An accidental fire in the room next door causes the temperature in the storage room to increase to 87.5 °C. What will the pressure gauge read at this temperature? 1.What are you trying to determine? What will the pressure gauge read at this temperature? PfPf

Step 2: Identify what is given: P i = 35.0 atm T i = 23.2 °C T f = 87.5 °C

Step 3: Convert temperatures from °C to K T i = 23.2 °CT f = 87.5 °C = 23.2 °C = 87.5 °C = 296 K = 360 K

Step 4: Use equation to determine final volume: P i P f T i T f 35.0 atm P f 296 K 360 K P f = 42.7 atm = =