When methane CH4 is burned in oxygen, water and carbon dioxide CO2 are formed.

When methane CH4 is burned in oxygen, water and carbon dioxide CO2 are formed. How much and what mass of oxygen is required to burn 160 g of methane?

CH4 + 2O2 = CO2 + 2H2O
Molar mass of methane (according to the periodic table): M = 12 + 4 * 1 = 16 g / mol.
Methane amount: n = m / M = 160 g / 16 g / mol = 10 mol.
According to the reaction, 1 mol of methane reacts with 2 mol of oxygen, which means n (O2) = 10 * 2 = 20 mol.
Oxygen mass: m = n * M, M = 16 * 2 = 32 g / mol (according to the periodic table). m (O2) = 20 mol * 32 g / mol = 640 g.
Answer: the amount of oxygen is 20 mol, its mass is 640 g.