Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry > air&atm > Flashcards

air&atm Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

Methane

A
  • produced from the decomposition of organic compounds such as vege matter, animal dung or rubbish from landfills
  • colourless, odourless and flammable gas
  • one of the greenhouse gases causing the ↑ in global temp & therefore ↑sed greenhouse effect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are unburnt Hydrocarbons, CnH2n+2

A

they are organic chemicals that vaporise at rm temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

major source of unburnt hydrocarbons? (& why it occurs)

A

incomplete combustion of fuels(hydrocarbons) in the combustion engines –> why? bcos of insufficient oxygen gas present or insufficient time in the cylinder for all the fuels to be burnt completely in order to form CO₂ gas & h₂O–> causing the release of unburnt hydrocarbons such as octane, C8H18 which will escape into air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

oxides of carbon

A
  • poisonous odourless
    man made sources: incomplete combustion of carbon containing fuel/ petrol car engines (insufficient oxygen to react)
    Effect: [human] combine w haemoglobin in RBC, lesser O₂ transport –> less O₂ in body cells = die x_x
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

oxides of nitrogen (man made sources + characteristics of gas)

A
  • internal comb engines of vehicles as a result of rxn b/w N2 + O2 at v. high temp
  • N2 is v unreactive (↑ energy needed to break N triple N bonds)

N2 + O2 –> 2NO
2NO + O2 –> 2NO2

  • reddish brown , pungent, non flammable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

photochemical smog(what is it?)

A

presence of hazy brown air which reduces visibility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is smog(& what r its impacts on hoomans)

A

it is a mixture of smoke and fog which reduces the visibility of air, causing stinging eyes & breathing difficulties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

formation of photochemical smog

A

NO₂ reacted with unburnt hydrocarbons in the sunlight to produce ozone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

stage 1 of formationof photochemical smog & chemical eqn

A

reqs the presence of UV light from the sun to produce O atoms, O(g):
NO₂(g) + O₂ (g)–> NO(g) + O(g) + 0₂ (g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

oxides of nitrogen (natural source + its effects)

A
  • lightning –> heat energy released cause N2 and O2 to react

[human effect] breathing difficulty
[envi effect] dissolve in limewater to form acid rain –> corrodes buildings made up of metal and limestone (CaCO3) + kills marine life due to ↓ pH in water bodies + kills plants due to ↑ acidity of soils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

characteristics of ozone pt1(appearance, smell)

A

it is a pale blue, posionous gas with characteristic odour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

characertisitics of ozone pt2(chemical + effects on humans)

A

it is the main component of photochemical smog and it is:

  • highly reactive substance which can further combine w unburnt hydrocarbons to form lacrimators(tear gas)
  • 0₃ (g) is an allotorope of O₂, but it is diff from ordinary O₂(g)
  • breathing air w ozone is dangerous as it causes respiratory problems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

stage 2 of formationof photochemical smog & chemical eqn

A

oxygen atoms, O(g) reacts w oxygen molecules to form ozone

O(g) + O₂ (g) ⇌ 0₃ (g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

oxides of sulfur (natural sources + effects)

A
  • volcaninc eruptions
  • [envi effect] dissolve in limewater to form acid rain –> corrodes buildings made up of metal and limestone (CaCO3) + kills marine life due to ↓ pH in water bodies + kills plants due to ↑ acidity of soils
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

air pollution

A
  • condition whr air contains a high conc of certain chemicals that may harm living things/ damage non living things
  • caused by poisonous gases/ solid particles in the air
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

composition of air

A

nitrogen - 78%
oxygen - 21%
others - 1% (argon, CO2, water vapour)

17
Q

what is fractional distillation of liq air(& its use in industries)

A

it is the process of separating air into its constituent gases & it is an impt process esp for obtaining nitrogen & oxygen that is widely used in industries

18
Q

steps of fractional distillation of liq air

A
  1. removal of water vapor and CO₂ gas in the air by cooling these gases into solids that is easily removed by filtration
  2. liquefaction where dry air(air w/o water vapor) is liquified at a very low temp below their B.P. which is app -200*C and this is carried out under a combination of repeated cooling and compression with high pressure
  3. fractional distillation where liq air is then heated acc to the respective BPs in order to b fractionally distilled so that liq air can b separated into its constituents
19
Q

acid rain

A
  • acidic pollutants dissolve in water –> prod low ph rain
  • SO₂ dissolve in water to form sulfurous acid
    SO₂ + H₂O –> H₂SO3
  • O₂ further oxidises sulfurous acid to sulfuric acid
    2H₂SO3 + O₂ –> 2H₂SO4
  • both H2SO4 and HNO3 are strong acids
  • polluted pH will be less than 6 bc CO₂ is acidic gas that dissolves in water to form weak acid H₂CO3 (carbonic acid)
20
Q

in fractional distillation, which order will the gases vaporise?

A

Nitrogen will be the 1st to be vaporised and distilled over from the liq air and argon will b 2nd and oxygen last bcos the bp goes from lowest in nitrogen to highest in oxygen.

21
Q

measures taken to control/reduce ozone layer depletion

A
  • reduce use of CFCs –> replace w non - ozone depleting HCFC (hydrochloroflurocarbon) and HFC (hydroflurocarbon)
  • convert used CFCs from refrigerator/ aircon w chemicals to safe disposible subs
22
Q

what are each of the parts of catalytic converter used for?

A 
front pipe: designed to take gases from the engine cylinders and channel them to the exhaust
catalytic converter: designed to reduce the no. of harmful pollutants gases😁
centre section(middle silencer): designed to reduce noise
tailpipe(incl silencer): designed to further reduce noise & channel exhaust gases away from the vehicle
23
Q

what does catalytic converter help do?(which gases!!)

A

oxides of nitrogen and other undesirable gases such as CO and unburnt hydrocarbons emitted by the car engines are a major source of air pollution so when catalytic converters are installed in cars, it helps to reduce air pollution

24
Q

flue gas desulfurisation (5 steps + explain wat it is)

A

remove SO₂ from waste gases formed when fossil fuels undergo combustion
1) mix limestone + water to prod slurry droplets
2) slurry droplets sprayed into flue gas(waste gas when fossil fuels undergo combustion) with SO₂
3) SO₂ react woth slurry droplets forming CaSO3 (s)
CaCO3 + SO₂ –> CaSO3 + CO₂
4) CaSO3 further oxidises by atm O₂
2CaSO3 + O₂ –> 2CaSO4 (gypsum)
5) mainly CO₂ and air exits thru chimney

Calcium oxide can also be used
CaO + SO₂ –> CaSO3 (s)

25
Q

ceramic elements in the catalytic converter is coated w ?(LOOK AT THE NAME OF THIS THING BROOO)

A

catalyst! platinum, Pt, rhodium, Rh or Palladium, Pd

26
Q

other measures to reduce air pollution caused by motor vehicles(3)

A
  1. use new materials(such as lightweight alloys) instead of steel to make car bodies so that lesser fuel is req to power lighter car bodies
  2. use clean fuels, such as methanol and hydrogen(only water is produced WOW) bcos the products of combustion are harmless
  3. use electric cars that are battery-powered so as to reduce exhaust gas emissions
    in the long run, the best way to control air pollution is to burn less fossil fuels.
27
Q

what causes ozone layer depletion (characteristics)

A

CFC(cpds w chlorine, fluorine, carbon)

  • widely used in refrigerator coolants/ refrigerant coolant/ air con
  • destroy ozone when they travel up to strato, decomp to form chlorine atoms under light, react w ozone molecules to form chlorine oxide + oxygen
  • O3 molecules formed by photo chem rxn b/w O2 molecule and O atoms in atm
28
Q

what happens to CO, NO and unburnt hydrocarbons?

A

2CO(g) + O₂(g) –> 2CO₂(g)
2NO(g) + 2CO(g) –> N₂ (g) + 2CO₂(g)
2C₈H₁₈(l) + 25O₂(g) –> 16CO₂(g) + 18H₂O(L)

29
Q

catlaytic converter should be used with what type of petrol?

A

with “clean” unleaded petrol because they are easily poisoned by lead compounds, sulfur compounds, arsenic compounds etc

30
Q

flue gas desulfurisation (5 steps + explain wat it is)

A

remove SO₂ from waste gases formed when fossil fuels undergo combustion
1) mix limestone + water to prod slurry droplets
2) slurry droplets spraid into flue gas with SO₂
3) SO₂ react woth slurry droplets forming CaSO3 (s)
CaCO3 + SO₂ –> CaSO3 + CO₂
4) CaSO3 further oxidises by atm O₂
2CaSO3 + O₂ –> 2CaSO4 (gypsum)
5) mainly CO₂ and air exits thru chimney

Calcium oxide can also be used
CaO + SO₂ –> CaSO3 (s)

31
Q

processes that release CO₂

A

respiration: C6H12O6 (aq) + 6O2 (g) → 6CO2 (g) + 6H2O (l) + energy

combustion:
- fuel containing carbon + hydrogen –> CO2 + H2O formed, comb of natural gas, mainly methane
CH4 (g) + 2O2(g) –> CO2 (g) + 2H2O (l) - complete comb
if O2 is limited (incomplete combustion)
4CH4 (g) + 5O2(g) –> 2CO2(g) + 8H2O (l) + 2C (s) + heat

32
Q

processes that remove CO₂(2)

A
  1. Photosynthesis- 6CO₂(g) + 6H₂O(l) –> C₆H₁₂O₆(aq) + 6O₂(g)
  2. ocean uptake: the world’s oceans serves as a massive sink that traps CO₂. Most of the dissolved CO₂ in the oceans is used by plants( for ps) and marine organisms, most of it is eventually conv into CaCO₃ in the form of shells and skeletons of marine organisms and overtime the shells and skeletons of dead organisms settle on the seabed to form LIMESTONE, CaCO₃!
33
Q

4 effects of global warming

A
  1. melting of iceberg at the poles-> cause an increase in sea levels and flood in low-lying countries like the Netherlands:((((
  2. drought will ↓ the crop yield world-wide bcos the areas that are currently covered by vegetation may become deserts-> famine and hunger
  3. warmer temp on earth surface-> cause rapid evaporation of water from earth surface, CO₂(g) dissolve in the sea water will b driven out into the atm
    - > adds further to the greenhouse effect
  4. increased occurrence of unusual weather conditions such as warm spells, droughts, unexpected storms and hurricanes, floods and tsunamis in some impacts of the world

Chemistry (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions