# What form of the ideal gas law would you use to calculate the temperature of a gas?

##### 1 Answer

You can use any form of the Ideal Gas Law, but usually one form is more convenient, depending on the information given.

There are three forms of the Ideal Gas Law.

**Form 1**

If the question gives you the number of moles

**Form 2**

If the question gives you the mass

**Form 3**

If the question gives you the density

**EXAMPLE**

What is the temperature of a sample of ethane, C₂H₆, that has a density of 1.264 g/L at a pressure of 1 atm?

**Solution**

Since we know the density, it is more convenient to use Form 3.

The molar mass of C₂H₆ is 30.07 g/mol

(289.9 – 273.15) °C = 16.8 °C