# How to convert grams to moles Many chemical equations require that the amount of substance be in the unit of moles. This leads to a very common conversion in which the grams of the substance be converted into moles. First, find the molar mass of NaCl. Use the periodic table to find the mass of each element then multiply that To convert grams to moles, start by multiplying the number of atoms by the atomic weight for each element in the compound. Then, add all of your answers together to find the molar mass of the compound. Finally, divide the number of grams of the compound by the molar mass of the compound to find the number of moles. How to Convert Grams to Moles and Vice Versa. How to Calculate Mass Percent Composition. How To Convert Molarity to Parts Per Million in a Solution. Quiz Yourself Using These 20 Practice Chemistry Tests. Can You Define Molecular Mass? Review Your Chemistry Concepts. In chemistry, the mole is the standard measurement of amount. However, balances DO NOT give readings in moles. Balances give readings in grams. So the problem is that, while we compare amounts of one substance to another using moles, we must also use grams, since this is the information we get from balances. These worked example problems show how to convert grams to moles and moles to grams in chemistry. In order to determine the number of moles of a given compound, the first thing you need to do is find the molecular mass (or molecular weight) of the compound in question. Once you've done that, you need to determine how much the compound weighs physically (in grams). After you get both of these values, you need to divide the physical weight of. This video discusses how to convert from grams to atoms using dimensional analysis. To perform this conversion, convert grams to moles and then moles to atoms. Moles are the standard unit that is used in chemistry to express the amount of a chemical compound. Unfortunately, there is no method to measure moles directly, because we can only physically measure the amount of a compound in grams when we use an analytical balance.