When calculating the number of moles from grams, what must you divide by?

To calculate the number of moles from grams, it is essential to divide the mass of the substance in grams by its molar mass. The molar mass of a substance is defined as the mass of one mole of that substance, typically expressed in grams per mole (g/mol). It reflects the combined mass of all the atoms in a molecule of that compound or the mass of a single atom of an element, depending on whether you are considering a compound or an individual element.

When you perform this calculation, you are essentially using the relationship defined by Avogadro's number, which states that one mole of a substance contains approximately (6.022 \times 10^{23}) entities (atoms, molecules, etc.). By dividing the given mass by the molar mass, you convert the weight of the substance into a count of moles, thus allowing for proper stoichiometric calculations in chemical equations.

The other options do not provide the correct context for calculating moles from grams. The atomic mass pertains to the mass of an individual atom, which may not directly correspond to the molar mass of an element or compound when in its molecular form. The total number of neutrons or protons does not directly relate to the concept of m