Transcript SV-2.5-Water

6.4, 7.2, &7.4 Water
Water
 Canada has ____of the world’s fresh water supply. The
water supply is available as:
 ______water (e.g. Great Lakes, rivers)
 ______sources (e.g. underground aquifers)
 Water is an excellent ______which makes it not only
very useful in chemistry, but important for life.
 Being a good solvent, however does mean that it also is
great at __________________________________.
Water
 Contaminants
 _________– inert suspended particles (e.g. silt)
 _________– viruses, bacteria, algae
 _________– any dissolved substance (metals,
minerals, and other chemicals)
 Source of Contamination
 Untreated _____water (e.g. Ottawa River)
 _________/agricultural waste (e.g. Walkerton)
 Landfill _________ (e.g Chelsea landfill)
 _____fire emissions
 Impact
 Dead Zones
 _____________- is the increase in __________of
a substance as you progress up the food chain.
Drinking Water Treatment
 Municipal Water Treatment Process
1. _________– screens filter out large debris.
2. _________, _________, sedimentation – particles settle out
of solution.
Al2(SO4)3 can be used as a coagulant [along with Ca(HCO3)2]
2Al3+(aq) + 3SO42-(aq) + 3Ca2+(aq) + 6HCO3-(aq)
2Al(OH)3(s) + 3Ca(SO4)(s) + 6CO2(g)
Drinking Water Treatment
_________– water flows through layers of sand and
active carbon. This removes _________, _________,
and _________impurities
4. _________– Chlorine or other reagent is added to the
kill any microorganisms and react organic solvents.
5. _________– Air, O2 or O3 added to reduce unwanted
taste/colour.
3.
Drinking Water Treatment
6. _________– addition of sodium carbonate and calcium
hydroxide precipitates Ca2+ and Mg2+ out of water.
Ca2+(aq) + 2CO3-(aq)
Mg2+(aq) + 2OH-(aq)
CaCO3(s)
Mg(OH)2(s)
_________– small amounts of _______is added to help
prevent tooth decay.
8. ______-_________ – another treatment of chlorine to
remove any microorganisms. _________is added to
stabilize the _________so that it remains in solution
during transportation to your tap.
7.
Drinking Water Treatment
 Point of Use Water Treatment
 Less than ____ of municipally treated water is used for
drinking.
 Other treatment methods could include one or more of:





Boiling
_________
Chlorination
Reverse Osmosis
_______________
Waste Water Treatment
"Every time you drink a glass of water,
the odds are good that you imbibe at
least one molecule that passed through
the bladder of Oliver Cromwell. It's just
elementary probability theory?"
 Richard Dawkins
Waste Water Treatment
 _________waste
 Disease _________– e.g. Cholera
 Chemical release – e.g. nitrates, phosphates
contraceptives
 Oxygen depletion – ____________of waste by bacteria
has high BOD (biological oxygen demand). This can
_______the relatively little O2 that is dissolved in water
Waste Water Treatment
 Dead zone gulf of Mexico
 Chemical _______& oxygen ________
Waste Water Treatment
 Process
 ___________Treatment:

Screening, _______, settling, filtering
 ___________ Treatment


Aeration
___________