Find the mass of silicon reacted with 4.48 liters of oxygen.

Si + O2 = SiO2.
1) Find the amount of oxygen. To do this, divide the volume of oxygen by the molar volume: 4.48 / 22.4 = 0.2 mol.
2) According to the reaction equation, there is one mole of silicon for one mole of oxygen. This means that the amount of silicon substance is: 0.2 mol.
3) Determine the molar mass of silicon according to the periodic table: 28.
4) Find the mass of silicon. For this, the amount of silicon substance is multiplied by its molar mass: 0.2 * 28 = 5.6 g – the answer.