1. Purifying and Softening Water L.O: L.O: To know how to soften and purify hard water, and the pros and cons associated with this

2. Calgon – water softener http://www.youtube.com/watch?v=NIfa yRbEPDI

3. Try adding sodium carbonate to hard water what happens to the amount of soap needed?

4. Water Softeners Water can be softened using sodium carbonate. It immediately precipitates the calcium and magnesium calcium ions + Sodium carbonate  calcium carbonate + sodium ions Ca + + Na 2 CO 3  CaCO 3 + 2Na + Ion Exchange softeners The sodium ions (or sometimes hydrogen) are used to replace calcium and magnesium ions in the water. Carbon and silver are sometimes used to make ion exchange resins Calgons chemical name is sodium metaphosphate, it works in the same way as sodium carbonate

5. Softening hard water

6. Explain how an ion exchange softener works

7. Toxic Chemicals in Water Copper and lead from mining Copper and lead from mining Nitrates from fertilisers can cause ‘blue baby syndrome’, the layman’s term for baby’s with cyanotic conditions. Nitrates from fertilisers can cause ‘blue baby syndrome’, the layman’s term for baby’s with cyanotic conditions. How are things like this removed?

8. Most water although removed of salt is not suitable for drinking and must be purified first 1) Sieve to remove large objects 3) Clear water has chlorine added to it 2) Sand is used to filter fine objects

9. Stages in water treatment