The water cycle & purifying water

The water cycle:  

Evaporation from rivers, seats etc

condensation into clouds

Preciptation e.g rain, back to earth

Water purifying Process:

Filtered through screens to get rid of large solids

Ozone added to kill off algae, bacteria and pesticides(excess is destroyed)

Furtherfiltration, though sand and gravel, to get rid of more solids

Passed through activated carbon granules, which have a large surface areas and are therefore good at getting rid of pesticides.

Chlorine is used to get rid of remaining bacteria

stored with a little chlorine to ensure it is clean when it reaches our taps

Solvent= liquid into which to solute dissolves

Solute= material which dissolves

Ionic compounds are usually soluble, molecular/covalent compounds are usually insoluble

Solubility is given in g/100g of water

Has dissolved compunds/ions in it (mg or ca)

reacts with stearate ions in the soap to foam scum:

calcium ions+ stearate ions ---> calcium stearate (insoluble scum)

HARDNESS is measured as "calcium carbonate equivalent" in mg/dm^3