The mass percent of an element in a compound is the mass of the element (total mass of the element's atoms in the com-pound) divided by the mass of the compound (total mass of all atoms in the compound) times 100%. What is the mass per-cent of each element in acetaminophen? (See Problem 2.170.)

Mass percent is a way to express the concentration of an element in a compound. It is calculated by taking the mass of the element in the compound, dividing it by the total mass of the compound, and then multiplying by 100 to convert it into a percentage. This concept is essential for determining the proportion of each element in a chemical formula.

Acetaminophen, also known as paracetamol, has the chemical formula C8H9NO2. Understanding the chemical formula is crucial as it provides the number of atoms of each element present in the compound, which is necessary for calculating the mass percent of each element. Each element's contribution to the total mass can be derived from its atomic mass and the number of atoms in the formula.

Atomic mass is the weighted average mass of an element's isotopes, measured in atomic mass units (amu). It is used to calculate the total mass of each element in a compound. Knowing the atomic masses of carbon, hydrogen, nitrogen, and oxygen is vital for determining the mass of acetaminophen and subsequently the mass percent of each element within it.