1. The problem statement, all variables and given/known data a) An ideal gas has a pressure of 1atm, volume of 0.5m^3m temperature of 300k. Find the number of moles. b) Three moles of an ideal gas is at a pressure of 1x10^2 Nm^-2 and a temperature of 263K. Calculate the volume. 2. Relevant equations 1) PV = NRT 2) PV=NKbT R = gas constant; Kb = Boltzman's constant 3. The attempt at a solution I have found the answers to be a) 1.22x10^23moles and b) 65.6m^3. What I don't understand, is when to use which equation. Why can I not use equation 1) for question a) vice versa. Thanks.