CHEMISTRY EXTRA CREDIT QUESTION - Can YOU do it??

[eg23462]

One mole of nitrogen gas confined within a cylinder by a piston is heated from 0°C to 777°C at 1.00 atm.

a) Calculate the work of expansion of the gas in joules (1 J = 9.87 x 10^-3 atm·L). Assume all the energy is used to do work.
answer in J

(b) What would be the temperature change if the gas were heated with the same amount of energy in a container of fixed volume? (Assume the specific heat capacity of N2 is 1.00 J/g·K.)
answer in °C

[sunshinegirl]

a)

1. First, use pV=nRT to calculate V
1 atm *V = 1 mol*0.082 L atm/K mol * 273.15
V1 = 22.39 L

2. p1V1/T1 = p2V2/T2
Since a piston is involved, the pressure remains constant, volume changes.
V1/T1 = V2/T2
V2 = V1*T2/T1 = 22.39 L *1050.15 K/273.15 K = 86.08 L

3. Work is :
W = p*DeltaV = 1 atm*(86.08L-22.39L) = 63.69 atm*L = 63.69/(9.87 x 10^-3) J=6453 J

b)
Q = c*m*deltaT
Q = 6453 J
c = 1 J/gK
m = moles N2/molecular mass = 1/28 = 0.036 g

Calculate delta T

Apparently I can