Gas Laws
-study the relationships that exist between pressure, volume, temperature and amount (moles) of gas.

1. Boyle’s Law * Pressure-volume relationship * At constant temperature and amount, the pressure and volume of a gas are inversely proportional. * As pressure increases, volume decreases. * P1V1=P2V2

2. Charles’ Law * Temperature-volume relationship * At constant pressure and amount, the temperature and volume of a gas are directly proportional. * V1/T1=V2/T2

3. Gay Lussac’s Law * Pressure-temperature relationship * Under conditions of constant volume and amount, the temperature and pressure of a gas are directly proportional. * P1/T1=P2/T2

4. Combined Gas Law * P1V1/T1=P2V2/T2

5. Avagadro’s Hypothesis * Any two gases under the same conditions of temperature, pressure and volume will contain the same number of moles (same number of molecules) of gas.

6. Ideal Gas Equation * Links pressure, temperature, volume and number of moles of a gas. * PV=nRT * Ideal gas constant= 8.315 kPa dm3 mol-1 K-1 * Ideal gas constant= .08206 atm L mol-1 K-1 7. Dalton’s Law of Partial Pressure * The pressure of a mixture is equal to the sum of the pressures exerted by each gas in the mixture. * Ptotal= PA+PB+PC 8. Graham’s Law of Diffusion * At a constant temperature, volume and pressure, the rates of diffusion of a gas are inversely proportional to the square root of their molecular masses. * Rate of gas 1/ Rate of gas 2= square root of molecular mass of gas 2/ square root of molecular mass of gas 1 Behavior of Gases * Boiling- phase change between a liquid and a gas * Occurs when atmospheric pressure is equal to vapor pressure * Vapor pressure-pressure exerted on a liquid by the vapor (gas) of the liquid above it * As the number of vapor molecules increases, vapor pressure increases. * As temperature increases, vapor pressure increases. * As strength of IMF increases, vapor pressure decreases. * Normal boiling point- temperature at which a liquid boils at