O - Carbon Dioxide

Question 1

State the solubility of CO₂

Answer 1

Carbon Dioxide is soluble in water - between 1-3g will dissolve in a litre of water, depending on the temperature

Question 2

Due to the solubility of CO₂, give a benefit and a detriment to the planet

Answer 2

Benefit - reduces increase in global warming due to the increasing amount dissolved in the oceans
Detriment - the seas are naturally alkaline, but the increase in CO₂ makes them slightly acidic

Question 3

Give the equation for the reaction dissolved CO₂ undergoes in water

Answer 3

CO₂ + H₂O ⇌ H⁺ + HCO₃⁻

Question 4

Describe how the increased amount of CO₂ dissolved in the oceans is detrimental

Answer 4

It decreases the pH of the water, which harms many species and upsets ecosystems (e.g. molluscs and crustaceans can’t form or maintain their shells if the conditions are too acidic)
Although some species may not be directly harmed by the decease in pH, they can be affected by the change to the food chain they are a part of

Question 5

Name 2 ways in which the amount of CO₂ released can be reduced

Answer 5

1) Use less fuel

2) Use different fuels

Question 6

Describe a way in which less fuel could be used in an attempt to reduce CO₂ emissions

Answer 6

Increasing the efficiency of devices (such as engines, heating systems, industrial machines and domestic devices), therefore less energy needed, so less fuel is burned and thus less CO₂ released

Question 7

For nuclear energy as an alternative to CO₂ emitting fuels, give 4 disadvantages

Answer 7

1) Concerns over health dangers (e.g. links to leukemia and other illnesses)
2) Concerns over the risk of accidental leaks or major disasters (like Chernobyl)
3) Problems with waste disposal, since waste products remain radioactive for hundreds of years, so systems are need to store it safely and permanently
4) CO₂ is still produced during the mining, processing and transportation of nuclear fuels

Question 8

For Hydrogen as an alternative to CO₂ emitting fuels, give 3 disadvantages

Answer 8

1) Hydrogen is hard to store and transport, it can’t be liquefied easily and a gas under higher pressure is dangerous
2) Huge investments would be needed to set up a new supply infrastructure like we have for petrol
3) Although Hydrogen itself is a very clean fuel, producing it requires energy, which if the energy came from fossil fuels, them the problem hasn’t been solved

Question 9

Name 2 ways in which CO₂ can be removed from the air

Answer 9

• Photosynthesis

- Carbon Capture and Storage (CCS)

Question 10

Describe how the amount of photosynthesis was reduced by human activity, and state how it could be increased again

Answer 10

• Decrease due to deforestation
• Photosynthesis could be increased by reforestation schemes - planting large areas of fast-growing trees to increase photosynthesis and CO₂ removal

Question 11

Describe Carbon Capture and Storage (CCS) and why this could be a potential option for Britain

Answer 11

CCS involves capturing the CO₂ produced and storing it
In Britain, CO₂ from power stations could be pumped into porous rocks under the sea to be stored, because there’s a lot of porous rock under the North Sea, and the old infrastructure from the oil field could be used to transport it