Question

What is the ΔG under standard temperature for the following reaction between? NH3(s) → NH3(l) Given: NH3(s):ΔHf= –46.11 kJ; ΔSf=192.45 J/K NH3(l):ΔHf= –80.29 kJ; ΔSf=111.3 J/K

Answer 1

We are given the reaction:

NH3(s) → NH3(l)

NH3(s):ΔHf= –46.11 kJ; ΔSf=192.45 J/K
NH3(l):ΔHf= –80.29 kJ; ΔSf=111.3 J/K

The formula of the Gibbs' Free Energy ΔG is

ΔG = ΔHf - TΔS

Assume T = 25 degrees C
For NH3(s):

ΔG = –46.11 kJ * 1000 - (192.45 J/K*298K)
ΔG = - 103.460 kJ

For NH3 (l)

ΔG = –80.29 kJ * 1000 - (111.3 J/K*298K)
ΔG = - 113.457 kJ

Therefore the ΔG under standard temperature for the reaction is the difference between the products - reactants. Solve for this.