(07.03 mc) read the following reactions. reaction 1: cao(s) + co2(g) → caco3(s) reaction 2: h2o(g) → h2o(l) which reaction leads to an increase in entropy? only reaction 1 only reaction 2 both reaction 1 and 2 neither reaction 1 nor 2

Explanation:

Entropy (S) is a measure of the degree of spreading of energy within a system. The more ways that energy can be distributed, the greater the entropy.

Reaction 1

Entropy is decreasing.

The molecules of CO₂ are all moving in different directions and at different speeds, so the thermal energy is widely distributed among many microstates. When they become carbonate ions, they are locked in position in a crystal lattice. They can vibrate only slightly about their equilibrium locations. The number of microstates is enormously reduced, so entropy decreases.

Reaction 2

Entropy is decreasing.

The molecules of H₂O in the gas phase are all moving in different directions and at different speeds, so the thermal energy is widely distributed among many microstates. When they become liquid water, they can slide past each other, but few of them can escape into the vapour phase

Their mobility is greatly reduced. The number of microstates is greatly reduced, so entropy decreases.