Question

The specific heat of hydrogen gas at constant pressure is C_(P)=3.4xx10^(3)"cal"//kg^(@)C and at constant volume is C_(V)=2.4xx10^(3)"cal"//kg^(@)C. If one kilogram hydrogen gas is heated from 10^(@)C to 20^(@)C at constant pressure the external work done on the gas to maintain it at cosntant pressure is

Answer 1

Given :

Specific heat at constant pressure (Cp)= 3.4×10³ cal/kg°C

Specific heat at constant pressure (Cv) = 2.4×10³ cal/kg°C

Mass of hydrogen gas = 1kg

T₁ = 10°C = 283K

T₂ = 20°C = 293K

To Find :

The external work done on the gas

Solution :

• We know the relation Cp - Cv = R

           R = 3.4×10³ - 2.4×10³

           R = 1×10³cal/kg°C

• Work done = PΔV  = mRΔT

                = 1×1×10³×(293 -283)

                = 10×10³ Cal

                = 10⁴ Cal

The external work done on the gas is 10⁴ Cal