To calculate the molar mass of a compound, what must you do?

To determine the molar mass of a compound, you need to add the atomic masses of all the elements that make up the compound, taking into account the number of atoms of each element present in the molecular formula. Molar mass is defined as the mass of one mole of a substance, usually expressed in grams per mole (g/mol).

For example, if you have a compound like water (H₂O), you would look up the atomic masses of hydrogen and oxygen. Hydrogen is approximately 1.01 g/mol, and there are two hydrogen atoms in water, contributing a total of 2.02 g/mol. Oxygen has an atomic mass of about 16.00 g/mol. Adding these together gives you the molar mass of water: 2.02 g/mol + 16.00 g/mol = 18.02 g/mol.

This process of summing the atomic masses ensures an accurate calculation of the compound’s molar mass, which is crucial for stoichiometric calculations and determining how much of a substance is needed for chemical reactions.