Question

The specific heat of helium at constant volume is $ 12.6 \,J\,mol^{-1}\, K^{-1} $ .The specific heat of helium at constant pressure in $ Jmol^{-1}K^{-1} $ is about (Assume the temperature of the gas is moderate, universal gas constant, $ R = 8.314\, J\,mol^{-1}K^{-1} $ )

• A. 12.6
• B. 16.8
• C. 18.9
• D. 21

Answer 1

Answer: (D)

Given,
$C_{V}=12.6\, J\, mol ^{-1} K ^{-1}$
$R=8314 \,J \,mol ^{-1} K ^{-1}$
The specific heat of helium at constant pressure,
$C_{p}=C_{V}+R=12.6+8.314=21$