The answer is: C) mass of any substance to moles.
To converte mass to amount of substances, mass must be divided by molar mass (n = m ÷ M).
Molar mass M represent the mass of a substance divided by the amount of substance. If the formula is not correct, amount of substance is not correct.
For example, calculate molar mass of iron(II) chloride:
Atomic mass of iron is 55.8 g/mol.
Atomic mass of chlorine is 35.5 g/mol.
If compound is FeCl, molar mass would be 55,8 g/mol + 35,5 g/mol = 91,3 g/mlo, that is not correct.
If compound is FeCl₂, malar mass of compound would be:
55,8 g/mol + 2·35,5 g/mol = 126,8 g/mol, that is correct.
