For which of the following processes would ΔS have a negative value?

Question

For which of the following processes would ΔS have a negative value?

 

I. 2 Fe₂O₃(s) → 4 Fe(s) + 3 O₂(g)

II. Mg²⁺ (aq) + 2 OH ̄ (aq) → Mg(OH)₂(s)

III. 2NO₂ (g) → N₂O₄ (g)

I,II, and III

II and III only

I and II only

I only

I and III only

Answer 1

I. 2 Fe₂O₃(s) → 4 Fe(s) + 3 O₂(g) ... ∆S increases going from (s) to (g)

II. Mg²⁺ (aq) + 2 OH ̄ (aq) → Mg(OH)₂(s) ... ∆S decreases going from (aq) to (s)

III. 2NO₂ (g) → N₂O₄ (g) ... ∆S decreases going from 2 mol (g) to 1 mol (g)

II and III only