C10 - chemistry of the environment Flashcards
define groudnwater
water from underground
define aquifer
water from underground
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
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
why may some water be harmful even after treatment
-mosquito lays eggs
-algae grows
how to make dirty water safe for drinking
-boil it
-filter it
how to get pure water from seawater
simple distillation
how to check if water is impure
-melt below 0C
-boils above 100C
air percentages
78% - nitrogen
21% - oxygen
1% - other gases (argon, carbon dioxide, water vapor, noble gases)
things needed for combustion
-fuel
-heat
-oxygen
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
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)
order of gases rising in air separation
nitrogen, argon, oxygen, krypton, xenon
biggest expense when separating air
electricity to run for compression & expansion
experiment to measure % of oxygen in air
-100cm^3 of air in gas syringe
-copper in between gas syringe and another glass
-heat copper as syringe pumps air back & forth
-oxygen is used up to make Copper oxide which changes from brown to black = reaction is complete
-79% air left
how to reverse reaction in experiment to measure % of oxygen in air using
-fill syringe with helium
-copper is displaced from Copper oxide
common pollutant in the air
-carbon particles
-sulfur dioxide
-nitrogen monoxide
-nitrogen dioxide
-carbon monoxide
-carbon dioxide
(methane)
harmful effects of sulfur dioxide
-causes acid rain (react with water vapor in cloud & form sulfuric acid) = acidic soil, kills animals, corrode buildings
harmful effects of nitrogen oxides
-causes acid rain (react with water vapor in cloud & form nitric acid) = acidic soil, kills animals
-respiratory problems
-nitrogen dioxide = photochemical smog = global dimming (no photosynthesis, warmth, vitamin D)
harmful effects of carbon dioxide
-increases global warming = climate change = extreme weather conditions, less thermal energy loss to space
harmful effects of carbon monoxide
-toxic gas to humans (binds to hemoglobin)
harmful effects of methane
-increases global warming = climate change = extreme weather conditions, less thermal energy loss to space
harmful effects of carbon particles
-respiratory problems
-cancer risk
how is sulfur dioxide formed
-combustion of fossil fuels which contain sulfur compounds
-volcanos
how is nitrogen oxides formed
-made in air from complete & incomplete combustion of nitrogen from high temp & pressure in car combustion engines
how is carbon oxides formed
-complete & incomplete combustion of fossil fuels containing carbon compounds
(only carbon dioxide)
-respiration
-complete combustion of hydrocarbons
how is methane formed
-decomposition of vegetation
-waste gas from digestion of animals
example of greenhouse gases
-carbon dioxide
-methane
why is methane not used as a fuel
it is a worse greenhouse gas than carbon dioxide
ways to reduce climate change
-planting trees
-reduction in livestock farming
-decreasing use of fossil fuels
-increasing use of hydrogen and renewable energy, e.g. wind, solar
how to reduce sulfur dioxide
-use flue desulfurization - react sulfur dioxide with calcium carbonate to make calcium sulfite and carbon dioxide
CaCO3 + SO2 -> CaSO3 + CO2
how to reduce nitrogen oxides, carbon monoxide & hydrocarbon
-use a catalytic converter - uses a platinum as a catalyst to speed reaction (provide path with lower activation energy)
CO + O2 -> CO2
hydrocarbon + O2 -> CO2 + water
2NO + 2CO → 2CO2 + N2
which gases are released in
1) combustion of fuels
2) petrol combustion in cars
3) combustion in air from cars
1) CO, CO2, SO2
2) CO, SO2
3)NO, NO2, hydrocarbons
reaction between all hydrocarbon & oxygen
hydrocarbon + oxygen -> carbon dioxide + water
ways to reduce pollutants
-use low sulfur fuels
-use flue gas desulfurization
-use catalytic converter
define rusting
oxidation of iron (iron oxide)
things needed for rusting
-water
-oxygen
compound in unpolluted air
water vapor
elements in unpolluted air
-nitrogen
-oxygen
-argon
uses for water
1) industry
2) house
1) cleaning, making clothes
2) drinking, showering
note: there is more argon than any other gases in the 1%
note:
-sulfur dioxide can be used to manufacture sulfuric acid
-carbon dioxide is made in fermentation
-carbon dioxide & metal oxide is made in thermal decomposition of metal carbonates
-combustion of hydrocarbons result in carbon dioxide & water
-household water contains salts
-incomplete combustion = insufficient oxygen
