posted by mel on .
A balloon filled with 22.3 mol helium has a volume of 500. L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 38.0°C as it expands to a volume of 570. 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/°C·mol.)
q = mass He x specific heat He x (Tf - Ti) where Tf is final T and Ti is initial T. mass He is 22.3 mol and Cp is 20.8 J/mol*c. Solve for q.
work = -p(delta V) = -p(V2 - V1)
V2, V1, and p are given. Solve for work. Work will be in L*atm so multiply what you get by 101.3 J/1 atm to convert to Joules.
Delta E = q + w.
Post your work if you get stuck.
for q i got 70538.931
for w i got 7091
and for the change i got 77629.931
the last one was worng, are they all wrong?