A scientist collects a sample of carbon dioxide that contains 1.5 x 1025 molecules of CO2. In grams, what is the mass of the sample?

Answer 1

you have

1.5x10^25/6.02x10^23 = 24.9 mol of CO2

1 mol = 12 + 32 = 44g

so, you have 24.9 * 44 = 1095.6g of CO2