Unit 2.3 - The wider impact of chemistry Flashcards
What’s good about the chemical industry and obtaining materials for chemical processes?
Major sources of employment - towns have grown up around such centres
Where are industries usually sited?
Near sources of raw materials
Raw material sources that industries are often sited near
Iron
Ore
Coal
Water
Good transport
What’s it important for industries near sources of raw industries to provide?
A healthy and safe environment for workers and their families living near factories
Economic requirements of chemical industries
Safety
Good quality products
Efficiency
Well-paid and fulfilled workforce
What’s a major issue in the chemical industry and inn all aspects of modern life?
Energy
What’s the problem with our current energy supplies?
Finite and non-renewable resources of fossil fuels
Fossil fuels examples
Coal
Oil
Gas
Why are energy requirements increasing?
The population is expanding
Energy requirements for industry, transport, electricity generation, domestic heating…
Name the main sources of energy
Non-renewable
Renewable
Solar
Nuclear
Geothermal
Combustion or bacterial digestion of biomass
Sources of renewable energy
Wind
Water
Examples of biomass used for their combustion or bacterial digestion to produce energy
Animal wastes
Wood
Sugarcane
Why would hydrogen be a good fuel?
Only product of burning it is water
What is spoken about to be the “future fuel?”
Hydrogen
What’s the problem with hydrogen as a fuel?
Doesn’t exist naturally on Earth
Prepared via electrolysis - requires energy
What do fossil and biomass fuels derive from?
Energy acting on plants and microorganisms for millions of years (compressed dead plants and organisms)
How are fossil fuels obtained?
Mining
Drilling
Tar sands
Fracking
Will fossil fuels last forever? Why?
No, as they’re being obtained approximately 100x their formation rate
Essential process in an equation of using fossil fuels
CH2O + O —> CO2 + H2O
<—
Name an industrial process that releases huge amount of CO2 into the atmosphere
Making concrete
What does combustion do to the atmosphere?
Contributes huge amount of CO2
What’s happened in the last 100 years in terms of CO2?
The concentration of CO2 in the atmosphere has increased from 300ppm to 400ppm
Carbon neutrality
When CO2 released is taken back in by plants
The net effect is zero CO2
What are some things we can do to obtain carbon neutrality?
Replant trees + sugarcanes to match those burnt so that the CO2 consumed via photosynthesis equals or exceeds that generated during combustion
What’s good about nuclear power?
No CO2
What IS nuclear power?
Neutron-aided fission of uranium
How much mass is converted using nuclear power and through which equation?
Less then 14% using E = mc^2
What are the drawbacks of nuclear power?
Radioactive emissions (plutonium is a byproduct - 1 atom can kill you, it’s the most toxic material on earth)
Safe disposal of radioactive wastes
What’s the byproduct of nuclear power and what’s the issue with this?
Plutonium
The mos toxic material on earth - 1 atom can kill you
What is, on paper, a better method than nuclear power?
Fusion of hydrogen to form helium (as in the sun)
Why is the fusion of hydrogen to form helium technically a better form of energy production than nuclear power?
Higher % of mass into energy
Fewer radioactive problems
Do we fuse hydrogen to form helium to form energy?
No, technical issues have occurred
What is solar power based on?
Silicon or gallium arsenide semiconductor
What form of energy production is rapidly growing in use?
Solar power
What’s the UK average of energy produced by solar panels?
0.5kW per square metre
What is one of the main aims of green chemistry?
Use less energy in industrial processes
How can we use less energy in industrial processes?
Use lower temperatures and use catalysts
List some green principles for making chemicals and product with as little environmental impact as possible
High atom economy
Design for biodegradation
Use renewable raw materials
Saving energy + increase efficiency
Prevent pollution + accidents
Use catalysts
Avoid toxic materials and solvents
Prevent waste
What’s the best atom economy possible and why is it important?
100%
So that a high % of the mass of reactant ends up in the product (little waste)
Renewable raw materials examples
Plant-based compounds
How can we get our energy in more sustainable ways?
Get it from renewable sources
Renewable energy sources
Biomass
Solar
Wind
Water
How can we save energy?
Use as little as possible
What are traditionally used as catalysts?
Transition metals
What should we be developing in terms of catalysts?
Better catalysts and biocatalysts (e.g - enzymes)
Why is the use of catalysts an important green principle?
Carry out reactions at lower temperatures and pressures
Save energy and avoid high pressure plants
What should we ensure when reactions take place as a green principle?
That no undesirable co-products of by-products are released into the environment
What’s the issue with diesel engines?
They liberate toxic nitrogen oxides (NOx) into the atmosphere
What toxic materials should we ensure to avoid?
Solvents
What solvents should we b avoidingin particular?
Volatile organic compounds (VOC)
(Very environmentally damaging)
Why does climate data tend to be less reliable if it’s older?
fewer records
less accurate instruments
temperatures probably used to be estimates
How do you calculate the energy released per gram when something is combusted?
Mr
What is an indicator of a fuel being better than another?
producing more energy per gram
If something produced more energy per gram upon combustion than another material, what does this indicate?
it’s a better fuel
What should we do with CO2 if it’s unavoidable to have it as a by-product of a reaction?
find a use for it/find a way to store it
Which reactions have atom economies of 100%?
ones that have only the desired product as the product of the reaction
What’s the atom economy of a reaction if the only product we have is the thing we want?
100%
Why are polymers difficult to dispose of?
don’t biodegrade
microorganisms cannot break them down
last in landfill sites for many years
Name a type of material that’s difficult to dispose of and explain why
polymers
they don’t biodegrade
Why don’t polymers biodegrade? What does this lead to?
Microorganisms cannot break them down
They last in landfill sites for many years
Define atom economy
The amount of starting materials that become useful products
What does a chemical plant do?
Manufactures chemicals on a large scale
Why is having a high atom economy in a reaction important?
Less waste
Write an equation for the complete combustion of coal
C (s) + O2 (g) —> CO2 (g)
What are some environmental issues associated with using power stations? Explain the effects of these
Acid rain - damages trees and buildings made from rocks like limestone
Global warming - climate change = rising sea levels and ice caps melting
How do we determine the most environmentally friendly fuel?
Releases the least amount of CO2 per mole of fuel burnt
Why should sulphur compounds be removed from fuels?
Sulphur combines with oxygen to form SO2
SO2 reacts with rain water to form acid rain
Explain what is meant by a carbon neutral fuel
Fuel from renewable source
No net change in atmospheric CO2 levels
CO2 released is that absorbed through photosynthesis as the plant grew
Where do carbon neutral fuels come from?
Renewable sources
