Question

the students found that the volume of water increased when it froze. they constructed the following model of liquid and frozen water to illustrate how phase affects water molecule arrangement. liquid water frozen water key = oxygen = hydrogen the volume of water increases when water freezes because water molecules are composed of atoms from different elements. the arrangement of the molecules in the water changes. the components of a water molecule increase in mass. water molecules have a low density.

Explanation:

When water freezes, it changes from liquid to solid. The model shows that the arrangement of water molecules changes. In liquid water, molecules are more closely packed and can move around. In frozen water (ice), molecules form a more open, hexagonal lattice structure. This change in molecular arrangement causes the volume to increase.

• The first option is incorrect because the composition of water molecules (H₂O) remains the same whether it is liquid or frozen.
• The third option is wrong as the mass of water molecules does not change during the phase change (mass is conserved).
• The fourth option is not the reason for the volume increase. The low - density of ice (frozen water) is a result of the volume increase (since density = mass/volume, and mass is constant while volume increases, density decreases), not the cause.

Answer:

the arrangement of the molecules in the water changes.