Question

For a particular reaction at 221.9 °C, ΔG = -92.39 kJ/mol, and ΔS = 130.33 J/(mol·K).

Calculate ΔG for this reaction at -54.3 °C.

____________ kJ/mol

Answer 1

use the equation

ΔG = ΔH - TΔS

solve the  ΔH at 221.9 ºC

ΔG = -92.39 kJ/mol convert in to joules = -92390 J/mol

ΔS = 130.33 J/(mol·K)

T = 221.9 ºC = 273 + 221.9 = 494.9 K

-92390 J/mol = ΔH - 494.9 K (130.33 J/mol-K)

ΔH =  -92390 J/mol + 64500.317 = -27889.683 J/mol = 27.9 kJ/mol

now use this ΔH and ΔS values and find the ΔG values find the ΔG at -54.3 ºC

T = 273 - 54.3 = 218.7K

ΔG = -27889.683 J/mol - 218.7K(130.33 J/(mol·K))

ΔG = -27889.683 J/mol - 28503.171 J/mol

ΔG = 56392.854 J/mol convert in to kJ/mol by dividing with 1000

ΔG = 56.4 kJ/mol