Question

20.5)

Calculate ΔG^o for the reaction

   SiCl₄(g) 2Mg(s)
Calculate Delta So for the combustion of propane. C3H8(g) + 5O2(g) rightarrow 3CO2(g)+4H2O(g) Sustance C3H8 O2 CO2 H2O So(J/k.mol) 269.9 205.138 213.74 188.825
2MgCl_2(s) Si(s)

Substance                         SiCl₄             Mg(s)                MgCl₂(s)           Si(s)

ΔG^{o_{f(kJ/mol)                            -616.98                 0                                -591.79                       0}}

a)566.60kJ

b)50.38kJ

c)25.19kJ

d)- 25.19kJ

e)- 566.60kJ

Answer 1

Here, we use the formula for calculating Gibbs free energy of areaction :

ΔGo of reaction = ΔGo of products- ΔGo of reactants

= (- 2 x 591.79 + 0) - (-616.98 + 0) kJ/mol = -566.6kJ/mol

Therefore, corret answer of the reaction is :

(E) - 566.6 kJ/mol

Note : The negative sign of Gibbs free energy indicates thatthe reaction is spontaneous

Answer 2

- 25.19 or +25.19

check C and D, please.

Thank you