1. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS 1 Chemical quantities

2. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Why study chemistry? According to Sir Harry Kroto, chemistry is all about solving problems and having fun.

3. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Equations are useful summaries of reactions. When sparklers burn, bits of magnesium react with oxygen. The equation is: 2Mg(s) + O 2 (g)  2MgO(s) Writing equations

4. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Relative atomic masses Atoms are too small to be weighed on a balance, but their masses can be compared. Helium atoms are four times as heavy as hydrogen atoms.

5. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Finding formulae Chemists find the formulae of compounds by first finding the masses of elements that make up a compound. Here, red copper oxide is being reduced to copper.

6. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Reaction masses It’s important to know how much of one chemical reacts with another. When methane in natural gas burns, 16 grams of it react with 64 grams of oxygen.

7. © G. Hill and A. Hunt 2008 Edexcel Chemistry for AS Percentage yields Percentage yields are important to chemists. How much iron can we get from one tonne of pure iron oxide?