Environment

Question 1

What are five greenhouse gases?

Answer 1

water vapour, carbon dioxide, methane, nitrous oxide, and CFCs

Question 2

How does carbon monoxide have consequences for air pollution?

Answer 2

• Fossil fuels are burnt without enough air and carbon monoxide is produced.
• When breathed in, it prevents red blood cells from carrying oxygen as there is no space for haemoglobin.

Question 3

How would a fertiliser cause pollution?

Answer 3

• Fertilisers contain inorganic ions, such as nitrates, phosphorus, and potassium.
• The excess nitrates from fertilisers run off into ponds or rivers.
• The increase in nitrates causes an increase in reproduction of algae and aquatic plants.
• The algae prevent light from getting through the water, so the plants under the water cannot do photosynthesis and die.
• The algae eventually die too, because they run out of nitrates.
• Bacteria decay the dead plants and use up more and more oxygen for respiration.
• Water becomes anoxic (without oxygen) and all life in the water dies.

Question 4

How would sewage cause pollution?

Answer 4

• Sewage runs off into rivers and ponds.
• Decomposers (bacteria and fungi) decay the organic matter in sewage.
• The decomposers use up the oxygen in the water for respiration.
• The water becomes anoxic and life in water dies.

Question 5

What is the greenhouse effect?

Answer 5

• Radiation from the sun reaches the earth.
• Some energy is absorbed and warms the earth.
• Some energy is re-emitted as radiation.
• Some of the re-emitted energy is absorbed by greenhouse gases and re-emitted back to the earth - heat is trapped and earth’s surface and lower atmosphere warms up.

Question 6

What are the five consequences of deforestation?

Answer 6

• There is less photosynthesis and less CO₂ is locked away - more CO₂ in atmosphere.
• Burning of trees releases more CO₂ into the atmosphere - less O₂ also.
• Species lose habitats and become endangered.
• There is more washed away soil, causing leaching and erosion, because soil loses its anchor.
• Water cycle is disturbed: less transpiration and rainfall, causing droughts; more water runoff because there are fewer stems and litter and trunks, causing flooding.

Question 7

Why is there lots of methane in the environment.

Answer 7

• Cattle - cows belch methane.
• Methane is produced when organic matter is broken down by microorganisms in the absence of oxygen - water-logged rice paddies and decomposition of waste in landfill.

Question 8

What are four consequences of global warming?

Answer 8

• Polar ice caps melt - sea levels rise and cause flooding.
• Rainfall patterns change - more rain in some areas and droughts in others.
• Extreme weather events such as hurricanes and storms,
• Ecosystems are affected as well as their biodiversity.

Question 9

How does sulphur dioxide cause acid rain?

Answer 9

• Fossil fuels are burnt by cars, industries, heating, e.t.c.
• Sulphur dioxide is released from sulphur impurities in the fossil fuels burnt.
• The sulphur dioxide mixes with rain clouds to produce dilute sulphuric acid, which falls as acid rain.

Question 10

What are the consequences of acid rain?

Answer 10

• Acid damages leaves and releases harmful substances from the soil so it’s harder for trees to take up nutrients - death of trees.
• Acidification of lakes affects the ecosystems because many organisms cannot survive at more acidic pHs and so aquatic animals and plants die.
• Acid rain corrodes buildings.