Use the equation to answer the question.

Question

H O(l) + heat ⇄ H O(g)
A sample of water is at equilibrium at 100°C. Which statement best describes what will happen if liquid water is added to the system?
(1 point)
2 2
More liquid water molecules will change to water vapor until a new equilibrium is reached.
All of the liquid water molecules that are added will become water vapor.
All of the liquid water molecules that are added will remain liquid water.
More water vapor molecules will change to liquid water until a new equilibrium is reached.

Answer 1

In the given equilibrium reaction:

\[ \text{H}_2\text{O}(l) + \text{heat} ⇄ \text{H}_2\text{O}(g) \]

At 100°C, which is the boiling point of water, the system is at equilibrium between the liquid and vapor states.

When more liquid water is added to the system, according to Le Chatelier's principle, the system will respond to maintain equilibrium. This means that the addition of more liquid water will shift the equilibrium to the right to produce more water vapor, until a new equilibrium is reached.

Therefore, the correct statement is:

More liquid water molecules will change to water vapor until a new equilibrium is reached.