Use each equation to predict whether the relative entropy change is S(products) > S(reactants) or S(products) < S(reactants) and whether ΔS > 0 or ΔS < 0 for the chemical reaction represented. Justify your answer in each case.

Question

a. 2NH3(g)→N2(g) + 3H2(g)
b. 2Al(s) + 3F2(g)→2AlF3(s)

Answer 1

For the entropy, larger number of moles means more entropy. That will answer both a and b. I don't understand the rest of the question because of the funny symbols.

Answer 2

Thank you, but how do I solve for the number of moles? I believe the funny symbols are, respectively, are delta signs in front of the S and arrows in the chemical equations.

Answer 3

That answer I gave you are for gases only. You count the mols. For a you have 2 mols NH3 on the left and 4 mols on the right so an increase in mols means increase in entropy. b. You have 3 mols gas on left and zero on the right.