# Question #1c1be

##### 1 Answer

The molar volume of a gas is simply the volume *1 mole* of an ideal gas occupies under certain conditions for pressure and temperature.

For example, the molar volume of a gas at **STP** represents the volume *1 mole* of any ideal gas occupies at a pressure of **100 kPa** and a temperature of **273.15 K**.

In other words, if those conditions for pressure and temperature are met, 1 mole of *any* gas will occupy a volume of **22.7 L**.

You can determine the molar volume of a gas under any conditions of pressure and temperature by using the ideal gas law equation.

You can rearrange this equation to get

If the pressure is equal to **1 atm** and the temperature to **273.15 K**, you'll get

If you want to see what volume *1 mole* would occupy, simply replace **1**

**SIDE NOTE** *This is the actually the old definition of the molar volume of a gas at STP.*

If you have a pressure of **2 atm** and a temperature of **355 K**, you would get

So, under these specific conditions for pressure and temperature, *1 mole* occupies **9.71 L**. You would have

*2 moles*#-># #9.71 * 2 = "19.4 L"# *4.5 moles*#-># #9.71 * 4.5 = "43.7 L"# *0.05 moles*#-># #9.71 * 0.05 = "0.486 L"#

and so on.

As a conclusion, the molar volume of a gas represents the volume occupied by *1 mole* of any ideal gas under specific conditions for temperature and pressure.

If pressure and/or temperature change, the molar volume changes as well.