Question

Given the equation representing a phase change at equilibrium:

H2O(s) <==>H2O(l)
Which statement describes this equilibrium?
(1) The H2O(s) melts faster than the H2O(l) freezes.
(2) The H2O(l) freezes faster than the H2O(s) melts.
(3) The mass of H2O(s) must equal the mass of H2O(l).
(4) The mass of H2O(l) and the mass of H2O(s) each remain constant.

Answer 1

This is called a dynamic equilibrium. Therefore, the reaction is constantly going,  but the amount of the reactants and products stay the same for they are both reacting at the same rate. So the answer is 4).