Question

Determine the mass of hydrogen gas if 36 grams of water undergoes electrolysis to produce hydrogen and oxygen.

Answer 1

2.01 g H₂

Step-by-step explanation:

The chemical equation for the electrolysis of water is

2 H₂O ⇒ 2 H₂ + O₂

Convert grams of water to moles. The molar mass of water is 18.016 g/mol.

(36 g)/(18.016 g/mol) = 1.998 mol H₂O

Convert moles of water to moles of hydrogen by using the mole ratio. By looking at the chemical equation, you can see that for every 2 moles of water consumed, 2 moles of hydrogen is produced.

(1.998 mol H₂O) × (2 mol H₂/2 mol H₂O) = 1.998 mol H₂

Now that you have moles of hydrogen, you can convert to grams. The molar mass of hydrogen is 1.008 g/mol.

(1.998 mol) × (1.008 g/mol) = 2.01 g H₂

You will produce 2.01 grams of hydrogen