Question

Question 11.15 Given below are observations on molar specific heats at room temperature of some common gases.


Gas Molar specific heat (Cv)
(cal mol–1 K–1)

Hydrogen 4.87

Nitrogen 4.97

Oxygen 5.02

Nitric oxide 4.99

Carbon monoxide 5.01

Chlorine 6.17

The measured molar specific heats of these gases are markedly different from those for monatomic gases. Typically, molar specific heat of a monatomic gas is 2.92 cal/mol K. Explain this difference. What can you infer from the somewhat larger (than the rest) value for chlorine?

Chapter Thermal Properties Of Matter Page 296

Answer 1

In list all gases are diatomic .we know ,
Diatomic gases have 5 degree of freedom. But monoatomic gases have 3 degree of freedom.
Therefore , molar specific heat of diatomic gas = 5 × R/2 = 5 × 1.98/2 = 4.95 Cal/mol-k . it agrees with molar specific heats of given gases except Chlorine ( Cl) .


Actually ' monoatomic gas has only translational energy but for 'diatomic' gas has translational as well as rotational and vibrational energies. Hence, molar specific heat of diatomic gases are higher than monoatomic .
Molar specific heat of Chlorine is higher than other gases due to translational motion along with rotational and vibrational in Chlorine at room temperature.

Answer 2

Answer:

refer attachment ;)

Explanation:

hope it's clear.