Final answer:
Dividing grams by g/mol (molar mass) calculates the number of moles of a substance, using the relationship where moles equal mass in grams divided by molar mass.
Step-by-step explanation:
When you divide grams by g/mol (grams per mole or molar mass), you are calculating the number of moles of substance. This is based on the formula:
moles (n) = mass in grams (m) ÷ molar mass (M)
The molar mass is a measure of the mass of one mole of a substance. It can be expressed as the atomic or molecular mass in grams. Hence, if you have a certain number of grams of a substance and you divide by its molar mass, you will determine the number of moles.
correct option a) Molar mass