What volume of oxygen at S.T.P. is needed for the complete combustion of 10 dm³ of methane, and what volume of carbon dioxide is formed? All volumes are measured at the same conditions.

When 6 g of magnesium is burnt in oxygen, what mass of magnesium oxide is formed? (Mg = 24, O = 16)

Calculate the mass of calcium oxide obtained by heating 100 g of pure calcium carbonate. (Ca = 40, C = 12, O = 16)

A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Find its empirical formula. (C = 12, H = 1, O = 16)

Calculate the mass of calcium oxide obtained when 50 g of calcium carbonate is completely decomposed by heating. (Ca = 40, C = 12, O = 16)

Calculate the volume occupied by 0.5 mole of any gas at S.T.P.

Calculate the number of molecules in 8 g of oxygen gas. (O = 16, Avogadro number = 6.022 × 10²³)