2. Air By Mr. Bronks

3. Composition of Air Air breathed inAir breathed out 79% 21% 0.03%

5. Oxygen in Air The part of air that supports combustion or burning Used up by breathing so use in hospitals Also rusting or corrosion Rockets carry their own supply of Oxygen

6. Rocket Fuel?

7. Burning things When something is burned it reacts with oxygen. For example: Magnesium + oxygen Magnesium oxide Carbon + oxygen Carbon dioxide Sulphur + oxygen Sulphur dioxide The Fire Triangle Fire Fuel Oxygen Heat

8. Percentage of Oxygen When we cover the candle the oxygen is used up – the water rises to fill the gap We measure the rise and find it’s around 21% Candle Water Gas Jar

9. Testing for carbon dioxide Air Limewater turns milky/cloudy Limewater Proves Carbon Dioxide in Air

10. Testing for Water Vapour in Air Drops on the test tube Ice and Salt Cobalt Chloride Paper turns pink in the presence of water

11. CO 2 Catalyst A substance that speeds up a chemical reaction but is not used up in the reaction. Here platinum is used as a catalyst in this catalytic converter. CO 2 CO

12. CO 2 Catalyst A substance that speeds up a chemical reaction but is not used up in the reaction. Here platinum is used as a catalyst in this catalytic converter. CO 2 CO CO 2

13. Oxygen Catalyst speeds up reaction but is not used up – Manganese Dioxide Oxygen does not dissolve in the water

15. Test for Oxygen Relights a glowing splint Oxygen

16. Test for Oxygen Relights a glowing splint

17. Burning Magnesium in Oxygen Burns much brighter In fact goes crazy-nuts-bright-and-scary Oxygen

18. Very Bright Flame Burning Magnesium in Oxygen

19. White Powder remains- Magnesium Oxide Burning Magnesium in Oxygen

20. Add water 2MgO +H 2 O  2Mg(OH) Water

21. 2MgO +H 2 O  2Mg(OH) Water Red Litmus turns Blue colour proves liquid is a BASE

22. Very Bright Flame White Powder remains- Magnesium Oxide Burning Magnesium in Oxygen Add water and Red Litmus paper turns Blue colour proves liquid is a BASE

23. Rusting also needs Oxygen Just like the candle the steel rusts and oxygen is used up. The space is filled with water Steel wool Water Gas Jar 2 weeks later Rusted

24. Preventing Rusting Metals needs water and oxygen to rust

25. Preventing Rusting Plating Painting Greasing Dry Galvanising

26. Summary

27. H/W P233 Q 1,2,3,4,5.