Question

Calculate the change in Gibbs free energy for each of the following sets of ΔHrxn, ΔSrxn, and T.

Part A

ΔH∘rxn= 90. kJ , ΔSrxn= 152 J/K , T= 303 K

Express your answer using two significant figures.

ΔG =

  kJ  

Part B

ΔH∘rxn= 90. kJ , ΔSrxn= 152 J/K , T= 750 K

Express your answer using two significant figures.

ΔG =

  kJ  

Part C

ΔH∘rxn= 90. kJ , ΔSrxn=− 152 J/K , T= 303 K

Express your answer using two significant figures.

ΔG =

  kJ  

Part D

ΔH∘rxn=− 90. kJ , ΔSrxn= 152 J/K , T= 407 K

Express your answer using two significant figures.

ΔG =

  kJ  

Answer 1

Part A

ΔG∘ = ΔH∘-TΔS∘

ΔH∘rxn= 90. kJ , ΔSrxn= 152 J/K , T= 303 K

So ΔG∘ = = 90 X 1000 J - 303 X 152 = 43944 = 43.94 KJ

Part B

ΔG∘ = ΔH∘-TΔS∘

ΔH∘rxn= 90. kJ , ΔSrxn= 152 J/K , T= 750 K

ΔG∘ = 90 X 1000 - 750 X 152 = -24000 Joules = -24.00 KJ

PArt C

ΔG∘ = ΔH∘-TΔS∘

ΔH∘rxn= 90. kJ , ΔSrxn=− 152 J/K , T= 303 K

ΔG∘ = 90 X1000 - 303 (-152) = 136056 J = 136.06 KJ

Part D

ΔG∘ = ΔH∘-TΔS∘

ΔH∘rxn=− 90. kJ , ΔSrxn= 152 J/K , T= 407 K

ΔG∘ = -90 X 1000 - 407 (152) = -151864 J = -151.86 KJ