Biofuels

1.

1 point

Biogas contains...

Less energy than diesel and petrol.

As much energy as diesel and petrol.

More energy than diesel and petrol.

2.

1 point

Above temperatures of 60C, the production of biogas stops. This is because. Tick all of the correct answers.

The bacteria are denatured.

The bacteria die.

Enzymes in the bacteria die.

Enzymes in the bacteria are denatured.

3.

1 point

Which of the following are examples of fuels from biomass?
a) Alcohol
b) Biogas
c) Wood

a, b and c

a

a and b

4.

1 point

True or false?
Biogas is a more important energy resource in less economically developed countries.

True

False

5.

1 point

Biogas is produced in digesters by what sort of process?

Batch

Continuous

6.

1 point

Biogas contains...

Mainly methane with some carbon dioxide and traces of hydrogen, nitrogen and hydrogen sulfide.

Mainly carbon dioxide, with traces of methane, hydrogen, nitrogen and hydrogen cyanide.

Mainly carbon dioxide, with traces of methane, hydrogen, nitrogen and hydrogen sulfide.

Mainly methane, some carbon dioxide and traces of hydrogen, nitrogen and hydrogen cyanide.

7.

1 point

Biogas can be produced on a large scale using a...

digester

septic tank

fermenter

dung pit

8.

1 point

Bioethanol can be mixed with petrol to form...

Petroethanol

Petrogas

Biogas

Gasohol

9.

1 point

Biogas containing less than what percentage of methane is explosive?

10%

15%

20%

25%

10.

1 point

Biogas is produced by the action of...

Anaerobic bacteria

Aerobic yeast

Anaerobic yeast

Aerobic bacteria

11.

1 point

Biogas can be used for...

Burning to generate electricity.

Burning to produce hot water and steam for heating systems.

Used as a fuel for vehicles.

All of the above.

12.

1 point

Which of the following is not an advantage of using biofuels?

They can be 'carbon neutral'.

They produce fewer carbon particulates than fossil fuels.

They do not produce carbon dioxide when burned.

They are alternative sources to fossil fuels.

13.

1 point

Biogas containing more than what percentage of methane can be burnt in a controllled way?

20%

30%

40%

50%

14.

1 point

Gasohol is more economically viable in countries that have...

ample sugar cane

high food prices

a large coastline

small oil reserves

15.

1 point

The burning of biofuels does not cause a net increase in greenhouse gas levels if...
(Tick all appropriate answers)

They are burnt at the same rate as the biomass being produced.

The biofuels are burnt completely at high temperatures.

Areas of land are not cleared of other vegetation in order to grow crops for biofuels.

Food crops are not used as biofuels.

16.

1 point

Alcohol (bioethanol) is made by...

Yeast

Bacteria

Viruses

17.

1 point

In some areas, the large use of land to produce biofuels is resulting in loss of ________ and the extinction of species.