Find the mass of potassium oxide that is formed during the combustion of potassium with a mass of 117 grams

Let’s find the amount of potassium substance by the formula:

n = m: M.

M (K) = 39 g / mol.

n = 117 g: 39 g / mol = 3 mol.

Let’s compose the reaction equation. Let’s find the quantitative ratios of substances.

4K + O2 = 2K2O.

For 4 mol of potassium, there are 2 mol of potassium oxide.

The substances are in quantitative ratios of 4: 2 or 2: 1.

The amount of potassium oxide substance will be 2 times less than the amount of potassium substance.

n (K2O) = 1 / 2n (K) = 0.3: 2 = 1.5 mol.

Find the mass of potassium oxide.

m = n × M.

M (K2O) = 39 × 2 + 16 = 94 g / mol.

m = 94 g / mol × 1.5 mol = 141 g.

Answer: 141 g.