Question
What is the entropy change when $$1$$ $$mole$$ oxygen gas expands isothermally and reversibly from an initial volume of $$10\,L$$ to $$100\,L$$ at $$300\,K?$$
A.
$$19.14\,J\,{K^{ - 1}}$$
B.
$$109.12\,J\,{K^{ - 1}}$$
C.
$$29.12\,J\,{K^{ - 1}}$$
D.
$$10\,J\,{K^{ - 1}}$$
Answer :
$$19.14\,J\,{K^{ - 1}}$$
Solution :
$$\eqalign{
& \Delta S = 2.303nR\,\,\log \frac{{{V_2}}}{{{V_1}}} \cr
& \,\,\,\,\,\,\,\,\,\, = 2.303 \times 1 \times 8.314\,\,\log \frac{{100}}{{10}} \cr
& \,\,\,\,\,\,\,\,\,\, = 19.14\,J\,{K^{ - 1}} \cr} $$