Calculate ΔS° for each of the following reactions.

Question

a) 2HNO3(l) + 3H2S(g) --> 4H2O(l) + 2NO(g) + 3S(s)

b) PCl5(g) + 4H2O(l) --> 5Cl-(aq) + H2PO4-(aq) + 6H+(aq)

c) MnO4-(aq) + 3Fe2+(aq) + 4H+(aq) --> 3Fe3+(aq) + MnO2(s) + 2H2O(l)

Answer 1

Use the provided data table and add up the products, then subtract the reactants. Use the coefficients in the balanced equation, as well.

this is the mathematical expression:

ΔSrxn=(ΣnΔS products)-(ΣnΔS reactants)

So,

ΔSrxn=(4 ΔS_H2O(l) + 2ΔS_NO(g) + 3ΔS_S(s)))-(2ΔS_HNO3(l) + 3ΔS_H2S(g))