2. Green chemisty Flashcards Preview

AS CHEMISTRY > 2. Green chemisty > Flashcards

Flashcards in 2. Green chemisty Deck (19):

How does a catalytic converter work?

platinum , palladium and rhodium catalyst on a ceramic base, with increased surface area from aluminium oxide lumps. Absorption of CO and NO to the catalyst surface. Temp bonds formed between gas and catalyst which holds it in place. which weakens the chemical bonds a chemical reaction 2CO+2NO-->2CO2+N2 the co2 and N2 get DESORBED from the surface and diffuse away.


What else does a catalytic converter remove? and how?

unburnt hydrocarbons get absorbed onto the catalyst surface, as well as O2. The bonds weaken and the two react under the heat. to create water and oxygen.


5 principles of green chemistry?(there are 12 but fuck that)

1. reduces use of hazardous chemicals. 2.High atom economy processes. 3.use renewable resources. 3. use alternate energy souses. 5.ensure waste products are non-toxic, recyclable, biodegradable.


How do gasses absorb radiation?

the molecule vibrates more.


What is the greenhouse effect?

the process of the absorption and subsequent emission of infrared radiation by atmospheric gasses warms the lower atmosphere and the surface.


Name the three main greenhouse gasses?

water vapor, carbon dioxide, methane.


Why is international cooperation needed to reduce pollution?

  • Pollution travels across borders.
  • all countries are responsible. t
  • o share expertise.
  • to have laws for not being green.


Consequence of global warming?

  • ice caps melting.
  • more storms in the tropics.
  • heat waves
  • animal extinction.
  • river overflows
  • drought
  • rising oceans.


MEthods of carbon capture and storage?

  • Underground pours rocks.
  • old oil and gas fields.(can get more oil out)
  • Storing as carbonates- reacting with metal oxides.(requires a lot of energy, and is slow)
  • storing in the DEEP ocean


What does the ozone layer do?

locks out UV-c and most of UV-b which are hthe higher energy UVs. O2--->2O O2+O-->O3 (or 2O3--->3O2)


How do CFCs catalys ozone depletion?

CFC+UV--->Cl* +CFCl2 (or equ)

Cl*+O3---->ClO* +O2


any termination. Will be repeated thousands of times.


What other radical destroys ozone?



why are there still loads of CFC's in the atmosphere

still being released from fridges.

has a very long life.


WHy is CO harmful?

a poisonous gas, CO binds stongly to haemoglobin which reduces the capacity for Oxygen in our blood.


Ways of reducing CO?

burnt it to CO2

catalytic converter with NO.


Why are Nitrogen oxides bad?

NO2 and NO ---depelte ozone.

NO2-nitric acid for acid rain.

both are respiritatory irritants .


Why are unburnt hydrocarbons bad?

buta-1,3-diene, and benzene are the bad ones. They are human carcinogens.

The unburnt hydrcarbons react with NO2 to form low level ozone(using sunlights energy)- which at low levels is a serious pollutant and causing breathing difficulties and infection rate.


What does sustainabilty mean for chemists?

the development of processes that prevent the depletion of natural resourses.


What is CO2 used in?

  • soft drinks/ beer.
  • foam- eg to inflate polystyrene chips.
  • to put out fires.
  • as a solvent
  • decaf coffee (or beer hops)- supercritical CO2 removes it.
  • dry cleaning
  • toxic waste treatment- organic molecules disolve in super crit CO2
  • chemical synthisis.