What is the term for the ratio of the weight of a volume of liquid to the weight of an equal volume of water?

• A. Density
• B. Specific gravity
• C. Viscosity
• D. Concentration

Answer: (B)

The term that describes the ratio of the weight of a volume of liquid to the weight of an equal volume of water is specific gravity. Specific gravity is a dimensionless number that is a comparison of the density of a substance to the density of water. It allows for a straightforward understanding of how heavy or light a substance is in relation to water, which provides a basic reference point since the density of water is defined as 1 g/cm³ at 4°C.

Density refers to the mass per unit volume of a substance and is typically measured in grams per cubic centimeter (g/cm³) or kilograms per liter (kg/L). While density is fundamental to understanding specific gravity, specific gravity itself focuses specifically on the comparison to water.

Viscosity relates to a fluid's resistance to flow and does not concern weight directly, making it irrelevant in this context. Concentration measures the amount of a substance in a given volume, usually in terms of molarity or percentage, which is distinctly different from both density and specific gravity.

Therefore, specific gravity is the accurate term that summarizes the relationship between the weight of a liquid and the weight of water, making it the best answer for this question.