2.3 - The wider impact of chemistry Flashcards
Why are fossil fuels bad?
They release carbon dioxide into the atmosphere and oceans that contributes to global warming as there’re green house gases
How much has carbon dioxide levels increased by in the last 100 years?
by 30%
The supply of fossil fuels is falling and the consequential increase in price, What alternative sources are being sought?
Nuclear power, combustion of biomass, solar, wind, water energy
With the use of biomass fuels it is hoped that carbon neutrality will be achieved? What does carbon neutrality mean?
it means that the CO2 being generated when burning the fuels will be compensated for by that absorbed by the fuel during photosynthesis. (The CO2 consumed in their photosynthesis equals or exceeds that generated by their combustion)
What is biomass?
A plant or animal material used for energy production
CH20 + 02 —combustion—-> CO2 + H20
CH20 +O2 <–photosynthesis—- CO2 + H20
What is solar power? What can directly convert sunlight into electricity?
A renewable source that generates electricity directly
Solar/ photovoltaic cells
What is nuclear power? What is the current type of method used?
A non renewable source that generates electricity directly.
Fusion of Hydrogen to form Helium, as in the sun, which converts a higher % of mass into energy with fewer problems of radioactive products then older methods of nuclear power such as the fission of uranium
The aim of green chemistry us to make the chemicals and products that we need as little impact on the environment as possible. Give examples of ways you can do this:
Using renewable raw materials (plant based compounds).
Using as little energy as possible.
High atom economy so there’s little waste.
Develop better catalyst to carry out reactions at lower temps/ pressure, to save energy and cost of high pressure plants
Avoid the use of toxic materials and ensure there are no undesirable products are realised into environment
Biodegradable products
Avoid use of solvents that are bad for environment
What are condensation polymers?
Able to be broken down by water, making plastic items biodegradable
When carbon compounds burn, they react with Oxygen in the air to produce…
Co2 and H20
If there is an insufficient supply of Oxygen in combustion then incomplete combustion will occur. In this process the major carbon product product is instead… This is a toxix gas
Carbon monoxide (CO)
Give an example of catalytic converter?
Rhodium which is fitted to the exhaust system of vehicles. This reduces the amount of harmful gases carbon monoxide and nitrous oxide and instead converts them into Carbon dioxide and Nitrogen (which are much less harmfull)
2CO + O2 —— +rhodium–> 2CO2
2NO —–+rhodium–> N2 +O2
What causes acid rain?
Sulfur impurities such as gas SO2 that dissolves in the atmospheric water creating a weak sulphuric acid which then precipitates and falls onto Earth as rain.
