What is the change in the internal energy in Btulbm1 of air

What is the change in the internal energy in Btu*lbm-1, of air as its temperature changes from100 to 200 degrees Fahrenheit? Is there any difference if the temperature were to chance from0 to 100 degrees Fahrenheit?

Solution

sol:

Change in internal energy is = Cv(T2-T1)

Cv value for air is 0.718 kJ/kg.K = 0.1714913537782 Btu/lb. oF

Change in internal energy is = 0.1714913537782*(200-100)

= 171.49 Btu/lbm

b) There is same value in change in the internal energy when temperatures changes from 0 to 100 oF