Question

Calculate ΔSsurr at the indicated temperature for each reaction.

Part A

ΔrH∘= -264 kJmol−1 ; 298 K

Express your answer using three significant figures.

ΔSsurr =

JK−1mol−1

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Part B

ΔrH∘ = -264 kJmol−1 ; 86 K

Express your answer using two significant figures.

ΔSsurr =

JK−1mol−1

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Part C

ΔrH∘ = 125 kJmol−1 ; 298 K

Express your answer using three significant figures.

ΔSsurr =

JK−1mol−1

Request Answer

Part D

ΔrH∘ = 125 kJmol−1 ; 86 K

Express your answer using two significant figures.

ΔSsurr =

JK−1mol−1

Answer 1

formula useful here is
ΔSsurr = - [ΔrH∘]/T

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Part A

ΔrH∘= -264 kJmol−1 ; 298 K
ΔSsurr = - [ΔrH∘]/T = 264 x10^3 Jmol−1 / 298 K = 885.9 j mol-1/K

ΔSsurr = 886. j mol-1/K

part B

ΔrH∘ = -264 kJmol−1 ; 86 K
ΔSsurr = - [ΔrH∘]/T = 264 x10^3 Jmol−1 / 86 K = 3069.7 j mol-1 K-1
ΔSsurr = 3100. j mol-1 K-1

part C

ΔrH∘ = 125 kJmol−1 ; 298 K

ΔSsurr = - [ΔrH∘]/T = -125 x 10^3 Jmol−1 / 298 K = -419 . j mol-1 K-1
ΔSsurr = - 419. j mol-1 K-1

part D
ΔrH∘ = 125 kJmol−1 ; 86 K
ΔSsurr = - [ΔrH∘]/T = -125 x 10^3 Jmol−1 / 86 K= - 1453. j mol-1/K
ΔSsurr = -1500. j mol-1 K-1