For a diatomic gas, = 7/5. Likewise, every point on the adiabatic curve must also obey the ideal gas law P V = nRT . Problem 18: The temperature of a monatomic ideal gas remains constant during a process in which 4700 J of heat flows out of the gas. How much work (including the proper + or - sign) is done? Specific heat capacities and the first law of thermodynamics Heat is added to two identical samples of a monatomic ideal gas. In the first sample the heat is added while the volume of the gas is kept constant, and the heat causes the temperature to rise by 75 K. In the second sample, an identical amount of heat is added while the pressure (but not the volume) of the gas is kept constant. By how much does the temperature of this Answer: 45 K sample increase?