Using the reaction equation O2 + K = K2O, calculate the volume of oxygen if 390 grams

Using the reaction equation O2 + K = K2O, calculate the volume of oxygen if 390 grams of potassium entered into a reaction with oxygen.

Let’s implement the solution, compose an equation according to the condition of the problem:
m = 390 g. X g. -?
1. 4K + O2 = 2K2O – compounds, obtained potassium oxide;
2. Calculation of molar masses:
M (K) = 39.1 g / mol;
M (O2) = 32 g / mol.
3. Determine the amount of the original substance:
Y (K) = m / M = 390 / 39.1 = 9.97 mol.
4. Proportion:
9.97 mol (K) – X mol (O2);
– 4 mol – 1 mol from here, X mol (O2) = 9.97 * 1/4 = 2.49 mol.
5. Find the mass O2:
m (O2) = Y * M = 2.49 * 32 = 79.68 g.
Answer: to carry out the reaction, oxygen with a mass of 79.68 g is required.