1. Neutralisation Reactions acid + base  salt + water Acids and bases are chemically the opposite of each other. Mixed together they cancel each other out, producing neutral salt and water instead.

2. Acids There are only a few acids you need to know: Hydrochloric acid ……………. HCl Sulphuric Acid ……………… H 2 SO 4 Nitric Acid ………………….. HNO 3 Hint: You may come across the weak acids like citric acid (lemon juice), acetic acid (vinegar) and carbonic acid (part of acid rain). In an exam you will be given any extra details about them that you need to answer the question. Look at the formulae. What do all acids have in common? Check answer

3. Bases There are four groups of bases you need to know about: 1.Metal oxidese.g. CaO 2. Metal hydroxidese.g. Ca(OH) 2 3. Metal carbonatese.g. CaCO 3 4. Metal hydrogencarbonatese.g. Ca(HCO 3 ) 2

4. Summary Acids Hydrochloric Acid (HCl) Sulphuric Acid (H 2 SO 4 ) Nitric Acid (HNO 3 ) Citric Acid (lemon juice) Acetic Acid (vinegar) Bases Metal oxides e.g. CaO Metal Hydroxides e.g. Ca(OH) 2 Metal Carbonates e.g. CaCO 3 Metal Hydrogencarbonates e.g. Ca(HCO 3 ) 2

5. 1. Oxides + acid copper oxide + hydrochloric acid  copper chloride + water H2OH2O CuO+2HCl CuCl 2 +  baseacid saltwater base + acid  salt + water

6. 2. Hydroxides + acid Cu(OH) 2 ++H 2 SO 4  CuSO 4 2H 2 O copper hydroxide + sulphuric acid  copper sulphate + water baseacid saltwater base + acid  salt + water

7. 3. Carbonates + Acid CuCO 3 + ++CO 2 H2OH2O2HNO 3  Cu(NO 3 ) 2 copper carbonate + nitric acid  copper nitrate + water + carbon dioxide Neutralisation using carbonates produces carbon dioxide as well! base + acid  salt + water

8. 4. Hydrogencarbonates + Acid Cu(HCO 3 ) 2 + ++2CO 2 2H 2 O2HCl  CuCl 2 copper hydrogencarbonate + hydrochloric acid  copper chloride + water + carbon dioxide Neutralisation using hydrogencarbonates also produces carbon dioxide! base + acid  salt + water

9. pH 07 14 Strong acid Weak acid Neutral (e.g. water and salts) Weak alkali Strong alkali pH is a scale from 1 – 14. It measures how acid or alkaline a solution is.

10. Indicators Universal indicator produces a range of colours to tell you the pH of the solution you are testing. Other indicators work differently….

11. Litmus paper turns blue in alkalis and pink in acids. Phenolphthalein turns lilac in alkalis but is colourless in acids END

12. They are ionic compounds whose positive ions are hydrogen What do all acids have in common?