For the chemical equation H2O = O2 + H2, calculate the mass and amount of hydrogen substance

For the chemical equation H2O = O2 + H2, calculate the mass and amount of hydrogen substance obtained from 36 g of water.

Given:

m (H₂O) = 36 grams (mass of water)

To find:

m (H₂) (mass of hydrogen) =?

n (H₂) (amount of substance) =?

Decision:

36 grams = x mole

We write down the equation of a chemical reaction:

2 H₂O = 2 H₂ + O₂

2 mol = 2 mol

n (H₂O) = m (H₂O) / M (H₂O) = 36/18 = 2 mol

M (H₂O) = 2 +16 = 18 g / mol

n (H₂) = n (H₂O)

n (H₂) = 2 mol

m (H₂) = n (H₂) * M (H₂) = 2 mol * 2 g / mol = 4 grams.

Answer: m (H₂O) = 4 grams;

The amount of substance is n (H₂O) = 2 mol.