In order to jave 2.2 moles of potassium oxide, how many grams of potassium are needed

Answer is: mass of potassium is 172.04 grams

Balanced chemical reaction: 4K + O2 = 2K2O.

n (K2O) = 2.2 mol.

From chemical reaction: n (K2O) : n (K) = 2 : 4 (1 : 2).

n (K) = 4.4 mol.

m (K) = n (K) • M (K).

n (K) = 4.4 mol • 39.1 g/mol.

n (K) = 172.04 g.

n - amount of substance.

m - mass of substance.

M - molar mass.