Answer:
[tex]\boxed {\boxed {\sf 0.5 \ moles}}[/tex]
Explanation:
At standard temperature and pressure (STP), 1 mole of any gas has a volume of 22.4 liters. This applies to oxygen, so let's create a proportion.
[tex]\frac {1 \ mol}{22.4 \ L}[/tex]
Since we are trying to find the moles in 11.2 liters, we should multiply by that number.
[tex]11.2 \ L *\frac {1 \ mol}{22.4 \ L}\\[/tex]
The units of liters cancel.
[tex]11.2 *\frac {1 \ mol}{22.4 }[/tex]
Condense into 1 fraction.
[tex]\frac {11.2 }{22.4 } \ mol[/tex]
[tex]0.5 \ mol[/tex]
At STP, 11.2 liters of oxygen gas is equal to 0.5 moles of oxygen gas.
