Canadian Entry To Practice (CETP) Practice Test

The specific gravity of a substance is a dimensionless number that compares the density of that substance to the density of water. Specifically, it is defined as the ratio of the density of the substance to the density of water at a specified temperature, usually 4 degrees Celsius, where water has its maximum density. When the specific gravity is less than 1, it indicates that the substance is less dense than water, which means it will float when placed in water. Conversely, if the specific gravity is greater than 1, the substance is denser than water and will sink. Therefore, understanding specific gravity allows one to predict whether a substance will float or sink in water. The other options do not pertain to the concept of specific gravity. Chemical reactivity, ionic properties, and combustion efficiency relate to different aspects of a substance's characteristics and behaviors and are not determined by its specific gravity. Thus, option A accurately reflects the relationship between specific gravity and the behavior of substances in water.