It is known that 1 mol of a substance is equal to 6.02x10^3 particles. This is called the Avogadro's number. From this knowledge, we convert the mass of the substances given above into units of moles by using the molar mass.
12.01 g C ( 1 mol / 12.01 g) = 1 mol
44.08 g SiO2 ( 1 mol / 60.08 g ) = 0.73 mol
16 g of O3 (1 mol / 48 g) = 0.33 mol
16.04 g CH4 (1 mol / 16.05 g ) = 0.99 mol
So, the answers are carbon and carbon tetrahydride.
