# How do mole ratios compare to volume ratios?

##### 1 Answer

I'm assuming that you are referring to reactions between ideal gases, for which a relationship between mole ratios and volume ratios can be easily determined.

So, according to Avogadro's law, equal volumes of ideal gases contain the same number of moles **at the same temperature and pressure**. This means that if pressure and temperature are held constant, **1 mole** of *any ideal gas* will occupy the exact same volume.

**(1)**

The most common application of this principle is the molar volume of a gas at **STP** - Standard Temperature and Pressure. At **STP** conditions, which imply a temperature of **273.15 K** and a pressure of **1 atm**, 1 mole of any ideal gas occupies exactly **22.4 L**.

So, let's say you have a reaction that involves ideal gases at STP.

The mole ratio between

Let's assume we have **STP**, we know that 1 mole of each of these gases occupies 22.4L. According to **(1)**, this means that

The volume ratio between

So, for gaseous reactants and products that are at the same temperature and pressure, the **mole ratio** is equal to the **volume ratio**.