You are given 120g of Calcium. How many moles have you been given? (Ar =40)

Use the equationNumber of moles = Mass / Relative Atomic Mass. Look at what I draw on the whiteboard. It is a formula triangle. This will help you when you have different parts of the equation to get to the answer.Mass has to be in GRAMS.The mass is 120. The relative atomic mass is 40. Divide 120/40 = 3 moles of Calcium.