Chemistry Chapter 4 - Part 2
- Created by: elliebaxter
- Created on: 26-01-17 12:49
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- Chemistry Chapter 4 - Part 2
- Water treatment
- 1) passing the water through filter beds to remove large particles
- 2) Adding chlorine to kill microbes
- Dry counties boil large amounts of seawater (desalination) - very expensive
- Positives of fluoride
- No proof of harmful effect
- Reduces cavities on teeth and gives overall protection
- Prevents types of heart disease
- Only added in tiny amounts
- Negatives of fluoride
- Weakens bones and bone cancer
- Benefit is not significant enough
- Ethically wrong to give treatment without consent
- Can affect brain, learning difficulties
- Can't control people's intakes
- 1) passing the water through filter beds to remove large particles
- Rusting
- Both air and water are needed for iron to rust
- Hydrated iron (III) oxide = rust
- Preventing rust
- Paint
- More reactive metal
- Less reactive metal
- Oil or grease
- Test (nail in each) = tube a - calcium chloride to absorb water tube b - layer of oil and water tube c - nail with water and air
- Rust indicator turns blue when rust
- Sacrificial protection - zinc, magnesium or aluminium more reactive so rusts instead
- Both air and water are needed for iron to rust
- Water treatment
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