B6 - Biofuels Flashcards Preview

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Flashcards in B6 - Biofuels Deck (17):
1

What is the mass of plants called?

The mass of plants is called biomass.

2

What are biofuels?

Biofuels are fuels made from plants.

3

What is biogas?

Biogas is biofuel containing methane.

4

What is a digester?

A digester is a large container full of rotting organic material and bacteria.

5

Why is methane a problem in landfill sites?

Methane is a problem in landfill sites because it can explode if it builds up too much.

6

What percentage of biogas is carbon dioxide?

Biogas is about 40% carbon dioxide.

7

What other gases are found in biogas?

Traces of hydrogen, nitrogen and hydrogen sulfide gas.

8

How can the energy in biomass be released?

- burning fast growing trees
- using bacteria or yeast to ferment the biomass to produce methane

9

Describe how methane can be produced on a large scale.

Methane is made on a large scale using a digester. Waste is fed into the digester continuously, producing methane and carbon dioxide.

10

Explain what happens to enzymes when they are denatured.

Enzymes gain a lot of KE and vibrate more. They bounce off each other and lose their shape.

11

What type of waste is used to make biogas in Kenya?

Human and animal waste.

12

When biogas burns it releases energy. How can this energy be used in different ways?

- to generate electricity
- to produce hot water and steam for central heating
- as fuel for vehicles

13

What is gasohol?

Gasohol is a mixture of petrol and ethanol.

14

What are the advantages to biofuels?

- they are an alternative for fossil fuels
- they recycle carbon dioxide used by plants
- no particulates are produced when they burn

15

What is gasohol used for?

Gasohol is used as an alternative to fuels.

16

What are the disadvantages to biofuels?

- large areas of natural habitat is destroyed to grow crops for biofuels
- could lead to extinction of animal species

17

Why are biofuels good for countries with little oil reserves?

It reduces the cost of transporting large quantities of oil from other countries.