Maintaining Air Quality

Question 1

fractional distillation liquified air

Answer 1

1. air cooled & compressed into liquid
2. liquid separated into fractions by frac distillation in fractionating column
3. gases separated due to diffs in bp, n2 (lowest bp) distilled at top

Question 2

co source & effect

Answer 2

• incomplete combustion of c-containing fuels/petrol
  1. reacts w/ haemoglobin in blood to form carboxyhaemoglobin, reduce ability to transport o2
  2. cause headache, fatigue, breathing difficulty, death

Question 3

so2 source & effect

Answer 3

• combustion of sulfur-containing fuels/fossil fuels
• emission from volcanic eruption
  1. irritates eyes & lungs, cause breathing difficulties
  2. high levels -> lung inflammation (bronchitis)
  3. reacts w/ h2o to form rain water, corrodes metal structures & limestone buildings, harms aquatic life & plants
• so2 dissolve in h2o -> sulfurous acid
• sulfurous acid oxidise in air -> sulfuric acid

Question 4

NOx (no & no2) source & effect

Answer 4

• nitrogen reacting w/ o2 at HIGH TEMPS, during lightning activity & in car engines
  1. irritates eyes & lungs, cause breathing difficulties
  2. high levels -> lung inflammation (bronchitis)
  3. NO2 ONLY - reacts w/ h2o to form rain water, corrodes metal structures & limestone buildings, harms aquatic life & plants (nitric acid)

Question 5

unburnt hydrocarbons (petrol) source & effect

Answer 5

• released in vehicle exhaust fumes & chemical plants
  1. cause cancer (carcinogenic)
  2. reacts w/ no in presence of sunlight to form toxic ozone

Question 6

ozone depletion

Answer 6

• ozone pollutant @ atmosphere, layer protection against uv light @ stratosphere
  UV CAUSES:
  1. skin cancer
  2. genetic mutation
  3. eye damage

CHLOROFLUOROCARBONS (CFCs) - main cause damage, made of C, F, Cl
1. found in aerosol cans, fridges, air-con, plastic foam
2. decompose in UV light to form highly reactive Cl atoms
3. highly reactive Cl react w/ ozone molecules to form Cl oxide & o2, destroying ozone

Question 6

methane source & effect

Answer 6

• decay of plant & animal matter
  1. greenhouse gas, traps heat in atmosphere, global warming
  2. leads to droughts/floods in low-lying lands due to melting of polar ice caps

Question 6

catalytic converters

Answer 6

• in cars, convert CO, NOx, unburnt hydrocarbons into harmless substances
• honeycomb structure: large surface area volume ratio

Question 6

carbon cycle

Answer 6

1. photosynthesis
2. respiration
3. combustion of fuels

Question 6

flue gas desulfurisation

Answer 6

• calcium carbonate/oxide reacts w/ so2 to form calcium sulfite (CaSO3)
• o2 from air oxidises calcium sulfite to calcium sulfate (CaSO4)

Question 7

greenhouse gases & global warming

Answer 7

cos & h2o retain heat, maintain surface temp
- buildup co2, methane, n2o lead to global warming, temp RISES
- effects: unusual weather conditions (hurricanes, droughts, tsunamis), melting polar ice caps (floods)