# Physics Heat transfer question (will award BEST ANSWER) [Solved] Assuming ideal gas behavior the change in enthalpy of the nitrogen gas is given by:
H = nCpT
The molar heat capacity at constant pressure for an diatomic ideal gas like nitrogen is
Cv = (7/2)R
Hence,
Q =(5/2)nRT

A
Process A is a constant volume process. The heat transferred in such a process equals the change in internal energy of the gas.
Q = U

Assuming ideal gas behavior the change in internal energy of the nitrogen gas is given by:
U = nCvT
The molar heat capacity at constant volume for an diatomic ideal gas like nitrogen is
Cv = (5/2)R
Hence,
Q =(5/2)nRT

From ideal gas law
nRT = pV
follows for an constant volume process:
nRT = (pV) = Vp

Hence,
Q =(5/2)Vp = (5/2)V(p_f p_i)
= (5/2) 2000cm (1atm 3atm)
= (5/2) 2000m10m (- 2 1.0132510 Pa)
= -1013.25 J

B
Process B is a constant pressure process. The heat transferred in such a process equals the change in enthalpy of the gas.
Q = H

Assuming ideal gas behavior the change in enthalpy of the nitrogen gas is given by:
H = nCpT
The molar heat capacity at constant pressure for an diatomic ideal gas like nitrogen is
Cv = (7/2)R
Hence,
Q =(5/2)nRT

From ideal gas law
nRT = pV
follows for an constant pressure process:
nRT = (pV) = pV

Hence,
Q =(7/2)pV = (5/2)p(V_f V_i)
= (7/2) 2atm (3000cm 1000cm)
= (7/2) 21.0132510 Pa 2000m10m
= 1418.55 J

This post is last updated on hrtanswers.com at Date : 1st of September – 2022