Question

Read the following reactions.

Reaction 1: NaCl(s) → Na+(aq) + Cl−
Reaction 2: CaCO3(s) → CaO(s) + CO2(g)

Which reaction leads to an increase in entropy?

a
Only Reaction 1

b
Only Reaction 2

c
Both Reaction 1 and 2

d
Neither Reaction 1 nor 2

Answer 1

Answer: C

Step-by-step explanation:

Reaction 1 starts off with one mole of reactant and produces 2 moles of product. The increase in the number of moles, along with the fact that aqueous compounds are more disordered than solid compounds, increases the disorder and thus entropy.

Reaction 2 starts off with 1 mole of solid and produces 1 mole of solid and one mole of gas. The increase in the number of moles, along with the fact that gases are more free and disordered than solids, increases the disorder and thus entropy.