Chap 9 - environmental chem Flashcards
process of treatment of water
-screen the big items
-add coagulant; make soluble things insoluble (ppt & form sediment)
-filter sediment with sand
-add carbon; remove taste & smell
-add chlorine; kill pathogen & microbes
-add fluorine; prevents teeth enamel from decaying
-store water in reservoir
water tests (reversible reaction)
1) anhydrous Copper (II) sulfate + water ⇌ hydrated Copper (II) sulfate
white ⇌ blue
A CS major W suck- A Comp Sci major Will suck.
2) anhydrous Cobalt (II) chloride + water ⇌ hydrated Cobalt (II) chloride
blue ⇌ pink
define groudnwater
water from underground
define aquifer
water from underground
define microbe
tiny organisms
purpose of coagulant in water treatment
reacts with water to produce sediment
purpose of chlorine in water treatment
kill pathogens & microbes
why may some water be harmful even after treatment
-mosquito lays eggs
-algae grows
why may fluoride be added in water treatment
prevents teeth enamel from decaying
how to make dirty water safe for drinking
-boil it
-filter it
how to check if water is impure
-melt below 0C
-boils above 100C
how to get pure water from seawater
simple distillation
air percentages
78% - nitrogen
21% - oxygen
1% - other gases (argon, carbon dioxide, water vapor, noble gases)
what is decolorizing charcoal made of
carbon
things needed for combustion
-fuel
-heat
-oxygen
colour of metals
-all metals are silver except copper & gold
(brown & gold)
uses of nitrogen
-liquid N2 freezes food for transport - low reactivity & abundant supply
-fertiliser
uses of oxygen
-aerobic respiration
-welding in gas tanks
-fuel cell
uses of noble gases
-coloured lights (argon, neon, helium)
-fire extinguisher (argon)
-advertising signs
-balloons
why do people carry oxygen tanks when mountain climbing
-lower oxygen content
most reactive gas in air
-oxygen
-nitrogen & noble gases aren’t that reactive
how to separate gases in air
-pump air
-remove carbon dioxide & water vapor
-expand & compress gas to liquify it at -200C
-boil liquid & elements gases rises in order of lowest boiling point (fractional distillation)