Question

. At 1.00 atm, one mole of nitrogen gas is heated from 0 to 819°C in a cylinder constrained by a weightless piston. (a) Determine the joule value of the gas's work of expansion. Assume that all the energy is spent on work. (b) What would happen if the gas was heated with the same amount of energy in a container with a fixed volume? (Average specific heat capacity of N2 is 1.04 J/g*K.)

Answer 1

a.
Volume 1 mole N2 @ zero C =22.4 L
Volume 1 mole N2 @ 819 C (or 1092 K) = V =nRT/P = 1*0.08206*1092/1 = 80.6 L
delta V = 80.6 - 22.4 = 58.2 L
Then work = -pdV = -1*58.2 = -58.2 L*atm
-58.2 L*atm x 101.325 = ? J.
b.
If the volume is fixed then delta V = 0 and -pdV = 0