Calculate ΔS (for the system)
Calculate ΔS (for the system) when the state of 3.10mol of perfect gas atoms, for whichCp,m = 5/2 R, ischanged from 25°C and 1.00 atm to 125°C and 5.00 atm.How do you rationalize the sign of ΔS?
a. Though ΔS (system) is positive, the process canstill occur spontaneously if ΔS (total) is negative.
b. Though ΔS (total) is negative, the process can stilloccur spontaneously if ΔS (system) is positive.
c. Though ΔS (system) is negative, the process can notoccur spontaneously if ΔS (total) is positive.
d. Though ΔS (system) is negative, the process canstill occur spontaneously if ΔS (total) is positive.
Answer:
~~~~~~~~
delta S = delta S1 + delta S2
For the first step
delta S1 = Cpm ln Tf/Ti
delta S1 = 3.10 * 5/2 * 8.314 JK-1 mol-1 * ln (125+273) K /(25+273)K
= 18.7 J K-1
and for the second
delta S2 = q rev / T
qrev = -w = nRT ln pi/pf
delta S2= nR ln pi/pf = 3.10 * 8.314 * ln 1/5
= -41.48 J K-1
therefore delta S = 18.7 + (-41.48)
delta S = – 22.78 JK-1
a. Though ΔS (system) is positive, the process canstill occur spontaneously if ΔS (total) is negative., thisis because there must be a increase in entropy and hence delta Shave negative sign and more absolute value than delta S system.
b. As the temperature increases, 
Ssurr increases (becomes less negative),therefore, the higher the temperature, the more likely it is forthe reaction to occur.
c.The total entropy change is negative and so the reactioncannot occur.
d. As the temperature decreases, Ssurr increases, therefore, the lower thetemperature, the more likely it is for the reaction to occur.
"Our Prices Start at $11.99. As Our First Client, Use Coupon Code GET15 to claim 15% Discount This Month!!"
