Question

Calculate ?G

Answer 1

(a)

Delta G = Delta H - T(Delta S)

Delta H = 2[Hf NO] - [Hf N2 + Hf O2]

Delta H = 2(90.9) - (0 + 0)

= 181.8 kJ = 181800 J

Delta S = 2[So NO] - [So N2 + So O2]

Delta S = 2(210.76) - (191.61 + 205.14)

Delta S = 24.77 J/K

Delta G = Delta H - T(Delta S)

Delta G = 181800 - (298)(24.77)

Delta G = 174418.54 J = 174.42 kJ

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b)

Delta G = Delta H - T(Delta S)

Delta H = [Hf H2O(g)] - [Hf H2O(l)]

Delta H = [-241.82] - [-285.83]

= 44.01 kJ = 44010 J

Delta S = [So H2O(g)] - [So H2O(l)]

Delta S = [188.83] - [69.91]

Delta S = 118.92 J/K

Delta G = Delta H - T(Delta S)

Delta G = 44010 - (298)(118.92)

Delta G = 8571.84 J = 8.572 kJ

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c)

Delta G = Delta H - T(Delta S)

Delta H = [2(Hf H2O(l)) + 4(Hf CO2(g))] - [5(Hf O2(g) + 2(Hf C2H2(g))]]

Delta H = [2(-285.83) + 4(-110.53)] - [ 5(0) + 2(226.8)]

= -1467.38 kJ = -1467380 J

Delta S = [2(So H2O(l)) + 4(So CO2(g))] - [5(So O2(g) + 2(So C2H2(g))]]

Delta S = [2(69.91) + 4(213.74)] - [5(205.14) + 2(200.94)

Delta S = -432.8 J/K

Delta G = Delta H - T(Delta S)

Delta G = -1467380 - (298)(-432.8)

Delta G = -1596354.4 J = -1596.35 kJ