1. Lesson: Air

2. Science Differentiation in action Air contains: 78% nitrogen (N 2 ) 21% oxygen (0 2 ) 1% water vapour & other gases 0.03% carbon dioxide (CO 2 ) Air is a mixture! These figures are approximate.

3. Science Differentiation in action Why is air a mixture? 1. The gases that make it change in proportion or composition. 2.Its gases become liquids when cooled and can be separated one at a time. 3.When the right gases are mixed, air is formed. No heat is given out or taken in so no new compound is made.

4. Science Differentiation in action To show the amount of oxygen in air, carry out an experiment. What did you discover? The percentage of oxygen in air is _____ 21%.

5. Science Differentiation in action How would you show that there is carbon dioxide (CO 2 ) in air? Use _________ CO 2 turns limewater _____ AIR milky. limewater.

6. Science Differentiation in action How would you show that there is water vapour in air? Use __________________ Water vapour turns cobalt chloride paper from blue to _____ Water vapour No Water vapour Cobalt chloride paper pink.

7. Science Differentiation in action What happens when you burn a wooden splint in air? It burns easily. What changes are taking place?

8. Science Differentiation in action What happens when you burn magnesium in air? It burns easily. What changes are taking place? magnesium magnesium oxide

9. Science Differentiation in action 1. Which is the most abundant gas in air? Review Questions 2. Does the composition of gases vary in air? 3. What paper do you use to test for water vapour?

10. Science Differentiation in action Predict what would happen if you burned a wooden splint or magnesium in pure oxygen? Question to think about! Test tube of oxygen