The percent composition (by mass) of a compound can be calculated by dividing the mass of each element by the total mass of the compound.
LEARNING OBJECTIVES
Translate between a molecular formula of a compound and its percent composition by mass
The atomic composition of chemical compounds can be described in a variety of ways, including molecular formulas and percent composition.
The percent composition of a compound is calculated with the molecular formula: divide the mass of each element found in one mole of the compound by the total molar mass of the compound.
The percent composition of a compound can be measured experimentally, and these values can be used to determine the empirical formula of a compound.
percent by mass: The fraction, by weight, of one element of a compound.
The atomic composition of chemical compounds can be described using a variety of notations including molecular, empirical, and structural formulas. Another convenient way to describe atomic composition is to examine the percent composition of a compound by mass.
Percent Composition by Mass
Percent composition is calculated from a molecular formula by dividing the mass of a single element in one mole of a compound by the mass of one mole of the entire compound. This value is presented as a percentage.
