13.6 NOTES Temperature and Pressure Behavior

Temperature-Pressure Behavior of Gases As temperature increases, the pressure of a gas increases when the volume is constant Known as Gay-Lussac’s Law   P1/T1 = P2/T2 or P1T2 = P2T1 YOU MUST DO THE CALCUATION USING THE KELVIN TEMPERATURE

Example: A gas has a pressure of. 37 atm at 50 °C Example: A gas has a pressure of .37 atm at 50 °C. What is the temperature at standard pressure?

The Combined Gas Law Takes all three gas laws and combines them   Temperature, pressure, volume all change P1V1T2 = P2V2T1

Example: If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200 K, and then I raise the pressure to 14 atm and increase the temperature to 300K, what is the new volume of the gas?  

Nonideal Gas Behavior Gases are typically assumed to be ideal and behave according to kinetic molecular theory Gases have what is called nonideal behavior at high pressure or low temperature   Low temperature Particles move very slowly, which allows intermolecular forces to increase, which causes condensation High pressure Forces the particles to be close together, which allows the intermolecular forces to cause condensation

Ideal Gasses and Molar Volume Avogadro’s Law Equal volumes of gas at the same temperature and pressure have the same number of molecules ALL gases have equal molar volumes if measure at same temperature and pressure Molar Volume Volume occupied by 1 mole of a substance Molar volume at 0°C and 1 atm is 22.4 L. Can use volume quantities like mole quantities in balancing equations and solving stoichiometry problems.

2H2 + O2  2 H2O - Coefficients can be moles or volume - 2 moles H2, 2 L of H2