Question: 0.19 litre of an ideal monatomic gas (Cv,m = 3R/2) initially at 83 °C and 47 atm pressure undergo an expansion against a constant external pressure of 1.19 atm, and do 2.3 kJ of work. The final pressure of the gas is 1.19 atm. Calculate the change in enthalpy, ΔH.

Question

First, I calculated Vf using the equation W = -Pext(Vf-Vi) and found Vf to be 2170.18L.

Then, I used P1V1 = nRT1 to find n, which found to be 0.50075 moles.

Next, I used Tf = (PfVf)/(nR), and Tf = 55981.3 K.

Finally, I used ΔH = n(5R/2)(Tf - Ti) and found ΔH = 57929.19.

Can anyone tell me if that's correct? Thanks!

Answer 1

Opps, the question should be: 0.37 litre of an ideal monatomic gas (Cv,m = 3R/2) initially at 51 °C and 36 atm pressure undergo an expansion against a constant external pressure of 1.06 atm, and do 2.3 kJ of work. The final pressure of the gas is 1.06 atm. Calculate the change in enthalpy, ΔH. Report your answer in J.