Find the mass of metallic sodium, which is necessary for interaction with water to form sodium

Find the mass of metallic sodium, which is necessary for interaction with water to form sodium hydroxide weighing 486 g.

We draw up the reaction equation and place the coefficients: 2Na + 2H2O = 2NaOH + H2.
1) According to the periodic table, we find the molar mass of sodium hydroxide: 23 + 1 + 16 = 40.
2) Find the amount of sodium hydroxide substance. To do this, divide the mass of the hydroxide by the molar mass: 486/40 = 12.15 mol.
3) According to the reaction equation, there are two moles of sodium for two moles of hydroxide. This means that the amount of sodium substance is 12.15 mol.
4) Molar mass of sodium: 23.
5) Sodium mass: 23 * 12.15 = 279.45 g – answer.