thermochemistry, energy and enthalpy?

Question

A balloon filled with 24.9 mol helium has a volume of 558. L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 33.0°C as it expands to a volume of 625. L, the pressure remaining constant. Calculate q, w, and E for the helium in the balloon. (The molar heat capacity for helium gas is 20.8 J/°Cmol.)

Answer 1

P = 101.325 kN/m^2
∆T = 33°C
∆u = (33°C)(24.9 mol)(20.8 J/°Cmol.)
∆u = 17,091.36 J
V1 = (24.9 mol(22.4 L/ mol)(10^3 cm^3/L)(1 m^3/10^6 cm^3)(273 °K/293 °K)
V2 = (24.9 mol(22.4 L/ mol)(10^3 cm^3/L)(1 m^3/10^6 cm^3)(273 °K/293 °K)(303 °K/273 °K)
∆V = (24.9 mol(22.4 L/ mol)(10^3 cm^3/L)(1 m^3/10^6 cm^3)(273 °K/293 °K)(306 °K/273 °K - 1)
P∆V = (101.325 kN/m^2)((24.9 mol(22.4 L/ mol)(10^3 cm^3/L)(1 m^3/10^6 cm^3)(273 °K/293 °K)(306 °K/273 °K - 1)
W = P∆V = 620.9240 J
∆h = ∆u + P∆V = 17,712.28 J