Hard and soft water

Mind Map by dpatel383, updated more than 1 year ago
Created by dpatel383 almost 7 years ago


A Levels Chemistry C3 Mind Map on Hard and soft water, created by dpatel383 on 05/17/2013.

Resource summary

Hard and soft water
1 Scum
1.1 calcium ions react with soap to form scum
1.1.1 insoluble precipitate
1.1.2 more soap needed and used more money used
1.1.3 soapless detergent doesnt contain sodium stearate and wont react with calcium ions to form scum
2 scale
2.1 insoluble solid
2.2 reduces efficiency
3 lather
4 hard- contains dissolved compunds----magnesium and calcium
5 Benefits of hard water
5.1 bone development
5.2 teeth development
5.3 reduce heart disease
5.4 reduces risk of lead poisioning ans some intestinal cancers
5.5 increases overall lifespan
6 hard water can be either
6.1 temporary
6.1.1 can be softened by heating/boiling
6.2 permanent
6.2.1 remains hard even when heated/boiled
7 Softening Hard water
7.1 add washing soda - sodium carbonate
7.1.1 calcium+carbonate=calcium carbonate+sodium
7.2 ion exchange column contain resins
7.2.1 sodium or hydrogen ions in the resin calcium and magnesium exchanged with the sodium/hydrogen in the resin
7.3 temp hard water contain hydrogencarbonate ions(HCO3-)
7.4 hydrogencarbonate ions when heated decompose into carbonate ions which react with magnesium or calcium ions found in the hard which leaves us with either magnesium carbonate or calcium carbonate
7.5 limescale - as hard warer evaporates/heated some carbon dioxide is lost with the water and calcium carbonate reforms....can be easily removed by dissolving in a weak acid
7.6 drinkable water
7.6.1 filter beds remove smaller and smaller solids...if from river it would be passes through sieve to remove large objects
7.6.2 activated carbon---- charcoal that is broken up inro granules to increase surface area an then treated to give pieces a slight positive charge. some contaminents stick to filter which should be replaced regularly
7.6.3 ceramic filters with microscopic particles of silver - kill any microorganisms that might otherwise grow in the filter
7.6.4 Purify or enhance distillation--evaporate sea water and allow re condensation eleswhere leaving salt and impurities behind expensive screens made of metal---remove debris like leaves or twigs that are in the reservoir settlement tank - sand,soil settles out aluminium sulfate- makes particles of dirt clump together and settle ( aka coagulation or flocculation) filter bed - fine sand filters remaining particles (insoluble solid) add chlorine - to kill bacteria / (added in some area) fluorine - hardens teeth fluorine - reduce tooth decay and added only in tiny amounts but possible links with learning difficulties and unethical (no choice if we can have fluroine or not) carbon - remove/reduce chlorine levels an possibly other chemicals eg trace of pesticide ion exchange resin removes calcium magnesium mainly silver discourages bacterial growth on resin
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