How many grams of H2O is formed if 100 grams of O2 reacted with H2?

Let’s find the amount of oxygen.

n = m: M,

M (O2) = 32 g / mol.

n = 100 g: 32 g / mol = 3.125 mol.

We compose the reaction equation for the combustion of hydrogen.

According to the reaction equation, when 2 mol of hydrogen and 1 mol of oxygen interact, 2 mol of water is formed. Oxygen and water are in quantitative ratios 1: 2. The amount of water substance will be 2 times more than the amount of oxygen.

2H2 + O2 = 2H2O.

n (H2O) = 3.125 × 2 = 6.25 mol.

Let’s find the mass of water by the formula: m = n M.

M (H2O) = 18 g / mol.

m = 18 g / mol × 6.25 = 112.5 g.

Answer: 112.5 g.