1. Air & Oxygen

2. RAG Sheet & WordBank Red Amber Green (No idea) (Some clue) (Know it)

3. What is the difference between the two methods you could use to find the % oxygen in air?

4. The Atmosphere Mixture of gases which forms a blanket around the earth

5. Composition of Air Investigate the % of oxygen in the air, using a night light (MP) Main steps – Floating night light, lit, graduated cylinder over it – Water rises – Allow to cool, measure volume of gas left – Not very accurate, air is  oxygen

6. Issues with experiment Night light goes out without all oxygen being used up Graduated cylinder does not measure volume as accurately as gas syringe

7. Composition of Air To measure % oxygen in air using gas syringe (MP) Main steps

8. Composition of air Reaction: Copper + Oxygen  Copper oxide – Start with 100cm 3 of air (100%) – Volume at end of reaction 79cm 3 (79%) – Volume of oxygen reacted with copper = 21cm 3  21% oxygen

9. Why it’s more accurate More oxygen removed from air Gas syringe is more accurate at measuring volume

10. Practical worksheet

11. What is the difference between the two methods you could use to find the % oxygen in air?

12. What is the significance of: cobalt chloride limewater litmus glowing splint a lighting splint going out?

13. Composition of Air GasPercentage in dry air Nitrogen78 Oxygen21 Inert gases & carbon dioxide 1

14. Composition of Air To show that carbon dioxide & water vapour are present in air (MP) – Cobalt chloride paper goes from blue to pink in presence of water – Limewater goes milky/cloudy in presence of CO 2

15. Practical worksheet

16. Preparation of oxygen Decomposition of hydrogen peroxide Word equation Hydrogen peroxide  water + oxygen Chemical equation (HL) 2H 2 O 2  2H 2 O + O 2 – This reaction requires a catalyst – Substance which speeds us a chemical reaction but is not used up in the reaction itself – Catalyst in this reaction is manganese dioxide/MnO 2 MnO 2

17. Preparation of Oxygen (MP) Main steps – H 2 O 2 dropped on to catalyst – Oxygen produced is collected over water as it is only slightly soluble

18. Properties of oxygen (MP) Oxygen is neutral No change in colour of red litmus or blue litmus paper Oxygen relights a glowing split

19. Practical worksheet

20. Properties of oxygen (MP) Burning carbon in oxygen Another name for burning is combustion Rxn: Carbon + oxygen  carbon dioxide C + O 2  CO 2 Limewater turns milky Carbon dioxide + water turns blue litmus paper red  acidic gas Carbon dioxide quenches a burning split Denser then air

21. Practical worksheet

22. Properties of Oxygen (MP) Burning magnesium in oxygen – Burns much brighter in oxygen then in air – Magnesium + oxygen  magnesium oxide

23. Properties of Oxygen (MP) Magnesium oxide and water Word equation: Magnesium oxide + water  magnesium hydroxide – Red litmus turns blue  a base is formed

24. Properties of Oxygen - summary Physical PropertiesChemical Properties Colourless, odourless, tasteless gas Supports combustions, substance burn more vigorously Slight soluble in waterReacts with most elements to form oxides Slightly heavier then airNo effect on litmus

25. Summary of reactions with O 2 ElementReaction with O 2 Compound formed Effect of compound on moist litmus paper CarbonGlows brightly Carbon dioxide Blue litmus turns red (acidic) Magnesium Burns vigorously Magnesium oxide Red litmus turns blue (basic)

26. What is the significance of: cobalt chloride limewater litmus glowing splint a lighting splint going out?

27. Uses of Oxygen Breathing – Stored in cylinders – Used in hospitals and by mountain climbers Burning and welding – Acetylene in O 2 reaches 3000  C – Flame can cut through melting or melt metal and join them together Space rockets – Need to bring own oxygen to space for combustion

28. RAG Sheet & WordBank Red Amber Green (No idea) (Some clue) (Know it)

29. Worksheet Exam questions Mindmap