CAPP Chemistry Lab Practice Test

Specific gravity is the property commonly confused with density when analyzing biological specimens such as urine. Specific gravity measures the ratio of the density of a substance to the density of a reference substance, typically water for liquids. In biological contexts, specific gravity is particularly important because it accounts for the concentration of solutes in a liquid and provides insights into the hydration status and kidney function of an organism.

In the case of urine analysis, specific gravity can indicate the concentration of waste products and other substances, helping to assess hydration levels. While density is an absolute measure of mass per unit volume, specific gravity offers a comparative measure that is especially useful in biological specimens where solutes can significantly affect overall density. Understanding this distinction aids in accurately interpreting lab results.

Viscosity, molarity, and hardness are distinct properties that do not serve the same purpose in this context, hence they are not the correct choice for this question. Viscosity relates to a fluid's resistance to flow, molarity measures the concentration of solute in a solution, and hardness refers to the measure of how resistant a substance is to deformation or scratching, none of which directly correlate with the analysis of biological fluids in the same way that specific gravity does.