The number of molecules in oxygen with a volume of 44.8 liters is …?

Given:
V (O2) = 44.8 l
Vm = 22.4 l / mol
NA = 6.02 * 10 ^ 23 mol − 1

To find:
N (O2 molecules) -?

Decision:
1) Calculate the amount of oxygen substance:
n (O2) = V (O2) / Vm = 44.8 / 22.4 = 2 mol;
2) Calculate the number of oxygen molecules:
N (O2 molecules) = n (O2) * NA = 2 * 6.02 * 10 ^ 23 = 12.04 * 10 ^ 23 = 1.204 * 10 ^ 24.

Answer: The number of oxygen molecules is 1.204 * 10 ^ 24.