Find the change in entropy (in J/K) when 5.00 moles of an ideal monatomic gas are allowed to expand isobarically from an initial volume of 20 cm3 to a final volume of 100 cm3.
A)167
B)100
C)67
D)52
E)152

Question

Quizplus · Accepted Answer

The formula for the change in entropy of an ideal gas undergoing isobaric expansion is:
ΔS=nRln(Vf/Vi), 
where n is the number of moles, R is the gas constant and Vi and Vf are the initial and final volumes, respectively. 
Plugging in the given values, we get:
ΔS=(5.00 mol)(8.31 J/mol*K)ln(100 cm^3/20 cm^3)=67 J/K

Find the Change in Entropy (In J/K) When 5