How much water is needed to obtain 8 g of hydrogen?

The decomposition reaction of water is described by the following chemical reaction equation.

H2O = H2 + ½ O2;

According to the coefficients of the chemical equation, one mole of water can be obtained from one mole of hydrogen. The hydrogen molecule, like the water molecule, contains two hydrogen atoms.

Let’s determine the amount of substance in 8 grams of hydrogen.

M H2 = 1 + 1 = 2 grams / mol;

N H2 = 8/2 = 4 mol;

This amount of water substance must be taken.

N H2O = N H2 = 4 mol;