You can use grams to moles and moles to grams. In your case just grams to moles. So since you're given grams, you would divide that by the molar mass of CO2 because that's how many grams are in one mole. The mass for Carbon is 12.0104 g/mol and Oxygen it's 15.9994 g/mol so to find the molar mass you would add 12.0104 + (2*15.9994) which gives you a molar mass of 44.0095 g/mol. You divide your given mass (132g) by the molar mass, so there's 2.9993 moles or approximately 3 moles in 132 g of CO2.
