Zusammenfassung der Ressource
Hard and soft water
- Scum
- calcium ions react with soap to form scum
- insoluble precipitate
- more soap needed and used
- more money used
- soapless detergent
- doesnt contain sodium stearate and
wont react with calcium ions to form
scum
- scale
- insoluble solid
- reduces efficiency
- lather
- hard- contains dissolved
compunds----magnesium and
calcium
- Benefits of hard water
- bone development
- teeth development
- reduce heart disease
- reduces risk of lead poisioning
ans some intestinal cancers
- increases overall lifespan
- hard water can be either
- temporary
- can be
softened by
heating/boiling
- permanent
- remains hard
even when
heated/boiled
- Softening Hard water
- add washing soda - sodium carbonate
- calcium+carbonate=calcium carbonate+sodium
- ion exchange column contain resins
- sodium or hydrogen ions in the resin
- calcium and magnesium exchanged with the sodium/hydrogen in the resin
- temp hard water contain hydrogencarbonate ions(HCO3-)
- 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
- 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
- drinkable water
- filter beds remove smaller and smaller solids...if from river
it would be passes through sieve to remove large objects
- 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
- ceramic filters with
microscopic particles of
silver - kill any
microorganisms that might
otherwise grow in the filter
- 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