2.3 - The Wider Impact of Chemistry

Question 1

What 2 factors create the ‘energy problem’?

Answer 1

• fossil fuels are being rapidly depleted, burning fossil fuels releases Co2 into the atmosphere and oceans
• levels of co2 have increased from 300ppm to 400ppm in the last 100 years, leading to global warming through the greenhouse effect

Question 2

What are the alternative energy sources to fossil fuels?

Answer 2

Hydrogen, biomass, solar power, nuclear power

Question 3

What is hydrogen like as an energy source?

Answer 3

• it is a clean fuel that only produces water
• it doesn’t occur naturally on earth, so has to be produced, which is expensive and uses fossil fuels
• most common methods are natural gas reforming and electrolysis

Question 4

What is biomass like as an energy source?

Answer 4

• energy generated or produced by living or once living organisms
• most common materials are plants, wood and waste
• carbon neutral process (plants burnt/plants grown)

Question 5

What is solar power like as an energy source?

Answer 5

• capturing the energy from the sun and converting it into electricity (set up is still expensive)
• weather dependant (impractical due to the location of some houses)

Question 6

What is nuclear power like as an energy source?

Answer 6

• no polluting gases, does not contribute to global warming and has very low fuel costs
• large scale accidents are catastrophic
• waste is radioactive, which is expensive and difficult to dispose of.

Question 7

What are the aims of green chemistry?

Answer 7

• renewable raw materials (plantbased)
• as little energy as possible, increase energy efficiency
• use methods of high atom economy
• develop better catalysts to provide lower temps and pressure
• biodegradable products
• avoiding toxic materials and solvents that are bad for the environment

Question 8

What are the benefits of enzymes?

Answer 8

• lower temperatures and pressures can be used =, saving energy and costs
• operate in mild conditions and does not harm fabrics and food
• biodegradable and easily disposable
• they form pure products, removing the need for complex separation techniques

Question 9

What are the disadvantages of enzymes?

Answer 9

• enzymes activity is affected by temperature (it increases until the protein denatures)
• enzyme activity was affected by pH
• enzymes can be difficult to remove from liquid products