Some people make physical chemistry sound more confusing than it really is. One of their best tricks is to define it inaccurately, saying it is ‘the physics of chemicals’. This definition is sometimes quite good, since it suggests we look at a chemical system and ascertain how it follows the laws of nature. This is true, but it suggests that chemistry is merely a sub-branch of physics; and the notoriously mathematical nature of physics impels us to avoid this otherwise useful way of looking at physical chemistry