2. In order to know the oxygen properties let us watch this video

3. Another nice video

4. The importance and uses of Oxygen Water consists of oxygen united with hydrogen. important in respiration. Important in food combustion in the living cell (this process produces the energy needed for life). The Ozone molecule is composed of oxygen atoms.

5. We also compressed oxygen in cylinders and use it in : 1.Mechanical ventilation for patients who suffer from breathing difficulties.

6. During surgeries.

7. During diving and climbing mountains because oxygen becomes lighter when we have rise above the Earth’s surface.

8. 4. €Oxygen is also used in cutting and welding metals when combined with acetylene gas to produce “oxyacetylene” flame whose temperature reaches 3500oC sufficient to melt metals.

9. Carbon Dioxide

10. How can you prepare CO 2 in the science lab???

11. How can you prepare CO 2 in your home??? Is Carbon Dioxide heavier or lighter than air??????

12. We have studied the properties of CO 2 Colorless and odorless. Heavier than air. What is your evidence? Easily dissolves in water, that is why it is not collected by displacing water. Doesn’t burn and doesn’t help in burning. Carbon dioxide extinguishes all burning processes except the magnesium ribbon. Why? You can search the internet for it.

14. Importance and uses of Carbon Dioxide Used in refrigeration by converting CO 2 into liquid by pressure and cooling. When the pressure is released Carbon dioxide turned into dry ice.

15. Carbon dioxide is used in extinguishing fires.

16. used to make soft drinks. What is the relation between CO 2 and soft drinks? Search the internet. If you want to know how much CO 2 in a bottle visit this website http://www.science- house.org/CO2/activities/co2/soda.htmlhttp://www.science- house.org/CO2/activities/co2/soda.html Is used to make bread as yeast produces CO 2 which cause the bread to become porous (filled with pores and holes) and tasty.

19. Nitrogen is a chemical element, while carbon dioxide is a chemical compound

20. Nitrogen is also called azote??? It means lifeless. Why is it called lifeless?????????? Because it doesn’t help in burning process and it is not included in the respiration process.

21. The Existence of Nitrogen In our atmosphere representing 78% of its volume. Nitrogen composes the most important part in the protein. Living organisms either they get their protein through the feeding process such as ………… and …………… Or they make their own protein such as ……….

22. Some plants can’t make their own protein such as clovers, peas and soybeans. So, how can they get their protein?????? They have a certain types of bacteria to supply these plants with the proteins they need.

28. Properties of Nitrogen Colorless, odorless and tasteless. Scarcely dissolves in water. What is your evidence? Doesn’t burn and doesn’t help in burning except with magnesium. When nitrogen is combined with lighted magnesium ribbon, a white substance is formed. When adding a little water the ammonia smell is emitted. Nitrogen can be condensed to liquid state.

29. - Liquid nitrogen is used for cooling food products with the aim of preservation or transferring purposes. Why??? This Video May Teach you Why.

30. - Nitrogen is used as an inactive material in the tanks of liquefied explosives and during the manufacture of electronic devices. Search the internet for the answer. -Nitrogen is used to make stainless steel. -Small amounts of nitrogen are used to fill some types of lamps. Search the internet for the answer.

31. Nitrogen is recently used in filling car tires for the relative constancy of its volume at the change of temperature.

32. It contributes in composing gunpowder and ammonium nitrates included in the composition of soil fertilizers.