Global warming and biogas

Question 1

2 main greenhouse gases

Answer 1

co2 and methane

Question 2

what releases co2

Answer 2

burning of fossil fuels

deforestation

Question 3

what releases methane

Answer 3

cattle

rice fields

Question 4

problems with the increase in temperature of the earth’s atmosphere… 5

Answer 4

1 climate change e.g. rainfall patterns
2rising sea levels
3 reduced biodiversity, extinct
4changes in species distribution and migration patterns
5 co2 dissolves in water, oceans lakes and ponds

Question 5

2 WAYS OF REDUCING THE PROBLEMS

Answer 5

BIOGAS

BIOFUELS

Question 6

how do we make biofuels?

Answer 6

sugar cane fermentation by yeast to make ethanol

Question 7

how do we make biogas?

Answer 7

bacteria carry out ANAerobic fermentation on carbohydrates - left over food or manure

Question 8

what is biogas?

Answer 8

methane

Question 9

why are biogas extractors placed in landfills?

Answer 9

to get rid of methane, powerful greenhouse gas

Question 10

Uses of biogas?

Answer 10

electricity, burned for heating and cooking

Question 11

small scale biogas generator advantages? 2

Answer 11

1 provides fuel for cooking, families

2 can be sited near the source of fuel e.g. cow shed

Question 12

what must you be careful of with small scale biogas generators?2

Answer 12

1temperature must be warm, if its cool the bacteria respires slowly
2 too hot, enzymes in bacteria demature

Question 13

small scale biogas generator 2 disadvantages

Answer 13

1cleaned out and refilled regularly
2 this reduces production
3 which means it is a batch process

Question 14

Advantages of large scale biogas generator 3

Answer 14

1provides large amount of biogas e.g. electricity
2optimum temperature can be controlled electronically
3 continuous process

Question 15

Disadvantage of large scale

Answer 15

the source of fuel must be transported, e.g. lorry.. diesel, more burning of fossil fuels releasing co2