Air and Water

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Across
  1. 5. Petrol is used on a global scale, therefore it damage properties and also create ____ issues to people
  2. 7. To prevent rust, people usually ____ it with paint, oil, etc or store it in a vacuum container
  3. 8. Oxides of nitrogen are formed from the heat and pressure found in a ____ ____
  4. 11. Gases like carbon monoxide, sulfur dioxide, etc are common ____ in the air
  5. 14. The compound added to coagulate small particles of clay so that they form larger clumps, which settle more rapidly
  6. 15. Blue anhydrous cobalt(II)chloride turns ____ in the presence of water
  7. 16. In industries, water is often used as a ____ to dissolve other substances or as a coolant
  8. 17. The process where water is passed through filter beds to remove different sized insoluble solids
  9. 18. Catalytic converters are used to ____ oxides of nitrogen
  10. 20. Carbon monoxide is produced in an incomplete ____ of carbon-containing substances leads to ____ ____
  11. 21. Air is a mixture of compound gases and mainly is the ____ gas
Down
  1. 1. Water has an unusually high ____ point for a molecule of its relative low molecular mass
  2. 2. Water is a neutral, colorless ____ that boils at 100°c and freezes at 0°c
  3. 3. The process of adding chlorine or chlorine compounds such as sodium hypochlorite to water to kill certain bacteria and harmful microbes
  4. 4. The common liquid air separation of oxygen and nitrogen
  5. 6. Water decreases in ____ when it freezes
  6. 9. A method to prevent rust by coating the less reactive metal with a more reactive metal as a sacrificial protection
  7. 10. White anhydrous copper(II)sulfate turns ____ in the presence of water
  8. 12. A gasoline that has been banned in some countries due to the lead compounds (a pollutant) that is produced
  9. 13. Water must be free of poisonous salts and harmful microbes otherwise it may cause various ____
  10. 19. When iron comes into contact with water and oxygen, it will ____