Question

why is an ice cube less dense than liquid water?
a. molecules in ice are more spread out than molecules in liquid water.
b. ice molecules have less mass than water molecules.
c. molecules in ice have less space between them than molecules in liquid water.
d. ice molecules have more mass than water molecules.

Explanation:

Density is mass per unit volume. In ice, water - molecules form a crystalline lattice with more space between them compared to liquid water. Since mass remains the same for the same amount of water in both states, the increased volume in ice due to the more spread - out molecular arrangement leads to lower density.

Answer:

A. Molecules in ice are more spread out than molecules in liquid water.