environment Flashcards
what is residence time
the average time a substance or mass spends in a specific place or medium
how do you calculate residence time
= amount of substance in the reservoir / rate inflow or outflow
does acid rain have short or long residence time
short, fairly local phenomenon,
what does acid rain cause soils to emit
Al3+
what is smog
combination of smoke and fog in the atmosphere made up of nitrogen, sulphur oxide, ozone …
examples of primary pollutants
volatile hydrocarbons
nitrogen oxides
examples of secondary pollutants
ketones
aldehydes
ozone (O3)
what is temperature inversion
cooler air skips underneath warmer air so the layer of war air is trapped inbetween 2 layers of cool air.
this causes any pollutants released in that layer of cooler air stay close to the earths surface. which allows the primary pollutants to react and produce secondary pollutants and smog
what is the normal condition in the Throposohere
temperature decreases as you go up. the warm and less dense air rises and takes pollutants with it.
the warmer air is then replaced with cool air which is again warmed up continuing the process.
what are the effects of PANs which can be found in smog
cause eye irritation and respiratory problems.
what are 4 air pollution concerns
ozone hole
global warming
acid rain
smog
name 4 fossil fuels we need to clean up
SOx
coal
NOx
soot (e.g. for diesil engines)
what is used to remove SO2 from the emissions of power plants
flue gas desulphurisation
how does the flue gas desulphurisation work
reacts flue gas with limestone
how can NOx emissions be reduced considerably
2 stage combustion technology
1st stage - high temperature and low O2. (not enough O2 to react with N2)
2nd stage - Excess O2, but low temp so that N2 cannot react to give NOx
how do power station remove NOx
they use ammonia
4NH3 + 4NO + O2 -> 4N2 + 6H2O
name 4 chemicals which impact to road pollution
NOx
particulate matter
CO
unburnt hydrocarbons
what is a three way catalyst
devise which reduces emissions from gasoline fuelled vehicles
what are the 3 tasks of a 3 way catalytic converter
- reduction of nitrogen oxides
- oxidation of CO -> CO2
- oxidation of unburnt hydrocarbons
what helps reduce harmful emissions from diesil engines
adblue
what is the definition of a critical element
elements crucial for technology development and the production of advanced energy.
what are 4 examples of critical elements
helium
lithium
phosphorus
zinc
platinum
where is shale oil extracted from
oil shale rock fragments underground
what is the process of fracking - used to extract shale oil (4 steps)
- holes are drilled into the shale rock
- fracking fluids are then pumped in
- high pressure cracks the rock allowing the oil to flow into collection wells
- oil and gas is collected and shipped away for use
what was the refined products of shale oil
- Lamp oil
- gas/fuel oil
- lubricating oil
what are 2 by products of shale oil
sulphur and ammonia
what are 3 environmental problems from modern shale oil
- the bings - artificial hills made from the remnants of shale oil
- fires in storage tanks and transport
- uses lots of water
- high emissions
what are 3 environmental impacts from shale oil production
- uses lots of water
- leaking of fracking fluids into water causing contamination
- earthquakes near fracking sites
what is fugitive methane
methane which escapes during fracking and transport of natural gases.
what does PM stand for
particulate matter
what is considered a thick layer of PM
2.5
what is the pH of acid rain
< 5
what are the 2 main chemical which cause acid rain
nitric and sulphuric acid from NOx and SOx emissions
what is the difference In aluminium recycling to glass recycling
glass in more energy intensive.
however adding waste glass to silica makes it easier to melt, so partial glass recycling is beneficial but not as much as Al recycling
what is the Gaia hypothesis
Organisms interact with their inorganic surroundings on earth to form a self regulating, complex system that contributes to maintaining the conditions for life on the planet.
what are the 5 environmental cycles
- Atmosphere - the layer of gases which surround the earth
- Geosphere - the solid part of the earth
- Hydrosphere - the sum of all water on Earth
- Lithosphere - the rocky outer part of the earth
- Biosphere - where life exists close to earth surface
what are the 2 keys points to remember for residence time
- Should use same mass units for reservoir amount and flux
- Find a level/volume when the outflow from the leaks is equal to the inflow
what is a reservoir
body of matter which has a relatively uniformly distributed physical, chemical or biological properties e.g. ocean, atmosphere, biosphere
Flux
amount of material entering or leaving per unit time e.g. rain into ocean
source
flux of material going into a reservoir plus rate of creation within the reservoir e.g. creation of ozone in ozone layer.
sink
flux of material leaving reservoir plus rate of destruction within reservoir
steady-state
when sources and sinks are in balance and do not change with time so that the concentration M does not change with time.
what are the approaches to pollution control (there are 6)
- Dilution (not for persistent chemicals).
- End-of-pipe (collecting waste)
- Green chemistry
- Change consumer habits
- Cradle-to-grave analysis
- Driven by legislation and public opinion.
what does the ozone layer do?
protects life on Earth from UV and solar radiation and plays an important role on the radiation budget of the atmosphere. The evolution of the ozone layer is coupled with climate change
what is the chapman cycle
oxygen interacting with UV
- constantly being created and destroyed
what molecules have an ozone destroying cycle
CFCs
- chlorofluorocarbons
what is the process of CFC breaking the ozone layer
chlorine initiates the breakdown of ozone and combines with a freed oxygen to create two oxygen molecules
after each reaction Cl begins the cycle again with another ozone molecule
Cl can therefore destroy throusands of ozone molecule
write the reaction steps of how Cl destroys ozone
- Cl* + O3 -> ClO + O2
- ClO + O* -> Cl* + O2
- O2 + O* -> 2O2
how do you find the mass concentration
Ri = Mi / V (kg/m3)
how do you find the molar concentration
moles per unit volume (mol/m3)
how do you calculate number concentration
Ci = ni / v (1/m3)
how do you calculate number concentration
Fi = Vi / V (m3/m3)
1ppb = ?ppt
1000ppt
what is the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb for CFC-11
4.7
what are 2 greenhouse gases
co2 and Ch4
what is the greenhouse effect
occurs when gases in Earth’s atmosphere trap the Sun’s heat.
