1. Calculate the number of moles in 5.72 x 10^20 molecules of CO

2. Calculate the number of atoms in 1.20 moles of sulfur

3. Calculate the molar mass of Al2 (SO4) 3

Calculate in the mass in grams of 3.00 moles Ca

Answer: Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We do as follows:

5.72 g (1 mol / 180.16 g) (6.022 x 10^23 molecules / mole) = 1.90x10^23 molecules