Across
- 5. Turns blue in the presence of water
- 6. When the water is passed through filter beds to remove different sized insoluble solids
- 7. used to separate nitrogen and oxygen in liquid air
- 9. When the water is then sterilised, to kill microbes
- 10. Form by the combustion of leaded petrol
- 11. Form by the incomplete combustion of carbon-containing substances
- 12. ______ water helps the body to stay hydrated
- 13. Water is used as a ______ in industries
- 15. Covers more than 70% of the Earth
Down
- 1. Covers 78% of the air
- 2. Form by combustion of fossil fuels which contain sulfur compounds
- 3. Turns pink in the presence of water
- 4. Used to remove oxides of nitrogen
- 8. Form from the heat and pressure found in a car engine
- 14. Covers 21& of the air