To raise the temperature of 2 mole diatomic gas by 1°C at constant pressure, the required amount of heat is 120 cal. The amount of heat which goes as the gas's internal energy is almost:
Correct answer: C. 85.7 Cal
- A. 82.5 Cal
- B. 80 Cal
- C. 85.7 Cal
- D. 58.8 Cal
Explanation
Cp and CV for a diatomic gas is 7/2 R and 5/2 R respectively. The gas's internal energy is increase by only 0.71 of the supplied energy. The rest is used to do work against external pressure. 0.71 ×120 = 85.7 Cal
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About Molar Specific Heat of a Gas
Molar specific heat is the heat required to raise the temperature of one mole of a gas by one kelvin, expressed through Q = nCΔT. Questions compare the constant volume value Cv with the constant pressure value Cp, apply the ideal gas relation Cp − Cv = R, and identify how the thermodynamic process affects heat capacity.
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