Final answer:
The answer is d). The density of water decreases as it is cooled from 4.0°C to freezing because hydrogen bonds in liquid water are longer than they are in ice.
Step-by-step explanation:
The decrease in the density of water as it cools to freezing is due to the formation of a rigid, lattice-like hydrogen bond structure in ice, causing water molecules to be spaced farther apart than in liquid water. As water cools, the hydrogen bonds orient to form a rigid lattice-like structure, which is less dense than the liquid state because the water molecules are pushed farther apart. This is in contrast to most other substances, where the solid form is denser because the molecules pack more tightly together.
Furthermore, water reaches its highest density at about 4°C. Below this temperature, when water turns into ice, the rigid structure means that the molecules are spaced farther apart compared to the liquid form. This unique behavior of water is critical for life on Earth as it allows ice to float on liquid water, providing insulation for aquatic ecosystems during freezing temperatures.Unlike most substances, the solid form of water (ice) has a lower density than the liquid state. This is because the water molecules in ice are pushed farther apart compared to liquid water, resulting in ice being less dense.