Question

An 11.2 litre cylinder contains oxygen gas at STP. Assuming that oxygen behaves ideally at STP, how many molecules are there in the cylinder ?

Answer 1

There will be `3.01xx10^(23)` molecules of oxygen in the cylinder.

The molar volume of a gas is 22.4 litres at s.t.p. This will contain `6.02xx10^(23)` molecules.

So 11.2 litres will contain `(6.02xx10^(23))/(2)=3.01xx10^(23)` molecules.