2. LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END COMPUTER PRESENTATIONS FOR KS3 SCIENCE - CHEMISTRY ©2003, STEVE PARKER COMPUTER PRESENTATIONS FOR KS3 SCIENCE - CHEMISTRY ©2003, STEVE PARKER

3. 1 1 KS3 SCIENCE - CHEMISTRY KS3 SCIENCE - CHEMISTRY Acids

4. 2 2 pH SCALE

5. 3 3 The pH number for any substance tells us if it is an Acid, an Alkali or Neutral The pH number for any substance tells us if it is an Acid, an Alkali or Neutral11223344556677889910101111121213131414AlkalisAlkalisAcidsAcids NeutralNeutral

6. 4 4 pH SCALE Universal Indicator changes colour in response to the pH Universal Indicator changes colour in response to the pH11223344556677889910101111121213131414AlkalisAlkalisAcidsAcids NeutralNeutral

7. 5 5 pH SCALE Common Substances have the following pH Common Substances have the following pH11223344556677889910101111121213131414

8. 6 6 PROPERTIES OF ACIDS

9. 7 7 Carbonic Acid is a weak acid used to make drinks fizzy Carbonic Acid is a weak acid used to make drinks fizzy

10. 8 8 PROPERTIES OF ACIDS Acids have a sour taste Acids have a sour taste

11. 9 9 PROPERTIES OF ACIDS Acids can be Corrosive, and they can seriously damage living cells Acids can be Corrosive, and they can seriously damage living cells

12. 10 PROPERTIES OF ACIDS Hydrochloric Acid in digestive juices is useful for breaking down food in the Stomach Hydrochloric Acid in digestive juices is useful for breaking down food in the Stomach

13. 11 PROPERTIES OF ACIDS Acids contain Hydrogen e.g. Hydrochloric acid (HCl), or Sulphuric Acid (H 2 SO 4 ) and React to give off Hydrogen Acids contain Hydrogen e.g. Hydrochloric acid (HCl), or Sulphuric Acid (H 2 SO 4 ) and React to give off Hydrogen ZINC HYDROCHLORIC ACID HYDROCHLORIC ACID

14. 12 PROPERTIES OF ACIDS Acids contain Hydrogen e.g. Hydrochloric acid (HCl), or Sulphuric Acid (H 2 SO 4 ) and React to give off Hydrogen Acids contain Hydrogen e.g. Hydrochloric acid (HCl), or Sulphuric Acid (H 2 SO 4 ) and React to give off Hydrogen Hydrogen makes a distinctive “squeaky pop” Hydrogen makes a distinctive “squeaky pop”

15. 13 ACIDS & METALS

16. 14 ACIDS & METALS Metals above Hydrogen in the Reactivity Series react with acids to produce a Salt and Hydrogen Metals above Hydrogen in the Reactivity Series react with acids to produce a Salt and Hydrogen Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminium Al (Carbon C) Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminium Al (Carbon C) Most Reactive Least Reactive Zinc Zn Iron Fe Lead Pb (Hydrogen H) Zinc Zn Iron Fe Lead Pb (Hydrogen H) Copper Cu Silver Ag Gold Au Copper Cu Silver Ag Gold Au

17. 15 ACIDS & METALS For example, Calcium reacts with Hydrochloric Acid to produce Calcium Chloride For example, Calcium reacts with Hydrochloric Acid to produce Calcium Chloride H H H H ClCl Ca ClCl H HClCl + + + + H H ClCl

18. 16 ACIDS & METALS Metal Carbonates react with acid to produce a Salt plus Water plus Carbon Dioxide Metal Carbonates react with acid to produce a Salt plus Water plus Carbon DioxideOOOO C C H HClCl H HClCl O O H H H H ClCl Cu ClCl OO C COO OO + + + +

19. 17 ACID REACTIONS

20. 18 ACID REACTIONS Acids in the stomach can cause discomfort, and acids in the soil can harm crops Acids in the stomach can cause discomfort, and acids in the soil can harm crops Farmers can add Lime to neutralise the acid if needed Farmers can add Lime to neutralise the acid if needed

21. 19 ACID REACTIONS Different plants prefer different pH conditions Different plants prefer different pH conditions 11223344556677889910101111121213131414

22. 20 ACID REACTIONS Acid rain can damage buildings and harm plants Acid rain can damage buildings and harm plants