Answer:
When you know the number of moles that you expect, you will multiply by the molar mass of the product to find the theoretical yield in grams. In this example, the molar mass of CO2 is about 44 g/mol. (Carbon's molar mass is ~12 g/mol and oxygen's is ~16 g/mol, so the total is 12 + 16 + 16 = 44.