Question

What volume does 0.25 moles of oxygen gas occupy at STP ?

Answer 1

`\boxed {\boxed {\sf 5.6 \ L \ O_2}}`

Step-by-step explanation:

We are asked to find the volume of 0.25 moles of oxygen gas.

At standard temperature and pressure or STP, one mole of any gas has a volume of 22.4 liters.

We want to convert 0.25 moles of oxygen gas or O₂ to liters. We will use dimensional analysis, so we must set up a conversion factor.

`\frac {22.4 \ L \ O_2}{1 \ mol \ O_2}`

We are converting 0.25 moles of oxygen gas, so we multiply the conversion factor by this value.

`0.25 \ mol \ O_2 *\frac {22.4 \ L \ O_2}{1 \ mol \ O_2}`

The units of moles of oxygen gas cancel.

`0.25 *\frac {22.4 \ L \ O_2}{1 }}`

`0.25 * 22.4 \ L \ O_2`

`5.6 \ L \ O_2`

0.25 moles of oxygen gas occupy 5.6 liters at standard temperature and pressure.