Measuring the mass of an apple—or an elephant—may seem simple, but the physics behind it is a bit of a mystery.

Calculate the relative mass of the reactants and of the products. The large numbers in the equation show the ratio in which the substances react and are produced.

Finding the percentage of an element in a compound by mass To find what percentage of a compound is a particular element, you must first calculate the relative formula mass (M r) of the compound.

Adjusted body weight is used to calculate weight, which considers lean and fat mass. This tool can help provide more precise medical and nutritional assessments.