Answer this question without using numbers from the book (or anywhere else!) ΔS for the following reaction is positive. True or false?

Question

Answer this question without using numbers from the book (or anywhere else!)

ΔS for the following reaction is positive. True or false?

CaCO₃(s) => CaO(s) + CO₂(g)

the answer is: true

please explain why, thank you!

Answer 1

The reactant side of the equation has 1 mole of solid (very low entropy). The right side has 1 mole of solid, but also has 1 mole of gas (high entropy). So, ∆S is positive, i.e. entropy increased.