Chemguide: Support for CIE A level Chemistry


Learning outcome 4(b)

This statement deals with real gases, and how they differ from ideal gases.

Before you go on, you should find and read the statement in your copy of the syllabus.


This is covered in more detail than you will need on the Chemguide page about real gases.


In order to understand the topic properly, you need to read the whole of this page apart from the section about the van der Waals equation. You won't, however, be expected to remember anything specifically about compression factors.

You will, however, be expected to know why real gases differ from ideal gases in terms of the intermolecular forces, and the space taken up by the molecules.

You will also be expected to know that gases become less ideal at low temperatures and very high pressures, and why that is so.

There is a CIE multiple choice question which asked which is the most ideal gas, which is why I have included that small section.


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© Jim Clark 2010 (modified August 2013)