Question

The entropy change when an ideal gas under atmospheric condition at room temperature is allowed to expand from $\text{0} \text{.5} \, \text{L}$ to $\text{1} \text{.0} \, \text{L}$ and also is simultaneously heated to $\text{373} \, \text{K}$ will be

(Given: $\text{C}_{\text{v,} \, \text{m}} \, \text{=} \, \text{12} \text{.50 J K}^{- \text{1}} \text{mol}^{- \text{1}}$ and $\text{log} \, \text{1} \text{.25} \, \text{=} \, \text{0} \text{.1}$ )

• A. $\text{0.18 J }\text{K}^{- 1}$
• B. $\text{0.36 J }\text{K}^{- 1}$
• C. $\text{0.90 J }\text{K}^{- 1}$
• D. $\text{0.72 J }\text{K}^{- 1}$

Answer 1

Answer: (A)

$n=\frac{P V}{R T}=0.02$ moles

$\text{ΔS} \, \text{=} \, \text{nRln} \frac{\text{V}_{\text{2}}}{\text{V}_{\text{1}}} + \text{nC}_{\text{v,m}} \text{ln} \frac{\text{T}_{\text{2}}}{\text{T}_{\text{1}}}$

$\text{ΔS} \, \text{=} \, \text{0} \text{.12} \, \text{+} \, \text{0} \text{.06}$

$\text{ΔS} \, \text{=} \, \text{0} \text{.18} \, \text{JK}^{- 1}$