1. The Ideal Gas Law Objectives: 1. State the ideal gas law and describe its variables. 2. Describe the conditions in which the behavior of a real gas varies from that of an ideal gas. Key Terms: Ideal gas, real gas, gas constant

2. The Ideal Gas Law The ideal gas law attempts to describe the behavior of real gases under ideal conditions. Ideal Gas Formula: PV = nRT or P 1 V 1 /nRT 1 = P 2 V 2 /nRT 2 R is the gas constant (0.0821 atm-L/mol-K or 8.31kPa-L/mol-K ). – The value R is sometimes the universal gas constant and is used to predict the behavior of ideal gases. Example: A sample of pure nitrogen gas exerts a pressure of 1 atm. When cooled to a temperature of 0 o C it has a volume of 2L. How many moles of gas are present in the sample?

3. Exceptions to Dalton’s Law Although most gases adhere to the ideal gas laws there are instances were they don't. – Very high pressures - distance between the molecules becomes too small and volume is no longer negligible – Very low temperatures - kinetic energy of the molecules drops and attractive forces between the molecules increases