Answer:
[tex]\boxed {\boxed {\sf 117.6 \ L \ He}}[/tex]
Explanation:
Regardless of the type of gas, 1 mole at standard temperature and pressure (STP) occupies a volume of 22.4 liters. In this case the gas is helium (He).
We can set up a ratio.
[tex]\frac { 22.4 \ L \ He}{ 1 \ mol \ He}[/tex]
Multiply by the given number of moles.
[tex]5.25 \ mol \ He *\frac { 22.4 \ L \ He}{ 1 \ mol \ He}[/tex]
The moles of helium will cancel.
[tex]5.25 *\frac { 22.4 \ L \ He}{ 1 }[/tex]
[tex]5.25 * { 22.4 \ L \ He}[/tex]
Multiply.
[tex]117.6 \ L \ He[/tex]
5.25 moles of helium gas at STP is 117.6 liters of helium.
