Question

Calculate the standard entropy change for the reaction at 25 °C. Standard molar entropy values can be found in this table.

MgCl


2

(s)+

H


2

O(l)⟶MgO(s)+2HCl(g)

Answer 1

ΔS_rxn = ΔS_prod - ΔS_reactant

∆S_rxn = ∆S(MgO) + 2x∆S(HCl) - ∆S(MgCl₂) - ∆S(H₂O) = 26.9 + 2x186.9 - 89.6 - 69.9 = 241.2 J/K