Volume stored at STP

Question

2Na  + 2H2O     2NaOH   + 1H2

What volume in Liters of Hydrogen gas (H₂) would be produced in the following reaction if 46 grams of Sodium (Na) were completely reacted and the hydrogen gas was collected and then stored at STP?

Answer 1

2Na + 2H₂O ==> 2NaOH + H₂ ... balanced equation

Find moles of Na (use atomic mass of Na = 23 g/mol)

46 g Na x 1 mol Na / 23 g = 2 mols Na present

Find moles of H₂ produced from 2 mols of Na (use the stoichiometry of the balanced equation)

2 mols Na x 1 mol H₂ / 2 mols Na = 1 mols H₂ produced

Find volume of H₂ produced

At STP, 1 mole of any ideal gas is equal to 22.4 L (you should memorize this value)

1 mol H₂ x 22.4 L / mol = 22.4 liters of H₂