1. Acids and alkalis What can you remember?

2. What does the word ‘acid’ mean? Where does it come from?

3. Acid tastes Acid comes from the latin word acer, which means sharp. Acids are sharp tasting! (“Tangy”) (also the word acute comes from this)

4. What do you call a chemical that changes colour in acids and alkalis

5. Indicators Indicators are chemicals (coloured dyes) which change colour in acids and alkalis.

6. Can you name some indicators?

7. Litmus Turns red in acid Turns blue in alkali Litmus can tell us if something is an acid or an alkali, but it cannot tell us how strong the acid or alkali is

8. Universal Indicator It comes in the form of a paper

9. Universal Indicator It also comes in the form of a liquid

10. Other indicators Red cabbage and beetroot make excellent indicators

11. What do we call the scale we use the measure acidity?

12. The pH scale The strength of an acid is measured on the pH scale pH stands for the “potential of hydrogen”

13. Universal Indicator To measure pH, we need an indicator that has a different colour for each value of pH Universal Indicator

14. What do you call it when an acid is added to an alkali?

15. Neutralisation

16. What is produced when we add an acid to an alkali?

17. Neutralisation Acid + alkalisalt + water Both neutral

18. Can you give examples of everyday life of neutralisation?

19. Examples of neutralisation

20. What do these symbols mean?

21. Chemical Hazard Symbols Corrosive – dissolves metals, stone and skin Irritant – harms eyes and skin Flammable – burns easily Toxic – poisonous