Part 1 – Introduction to Unit 2



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Castlebrae Community

High School

NATIONAL 4 CHEMISTRY

Unit 2

Nature’s Chemistry

Question Booklet

Fuels

1. What is meant by the word ‘fuel’?

2. Give three ways in which the formation of coal and oil are similar.

3. We describe fossil fuels as being ‘finite resources’. What do we mean by this?

4. The questions which follow are based on the table below.

|C |N2 |H2 |

|He |O2 |CO2 |

a) These 2 gases make up more than 98% of the air.

b) All fuels need this gas to allow them to burn.

c) This gas turns lime water milky.

d) This gas relights a glowing splint.

e) This is a solid fuel.

f) This is a gaseous fuel.

5. Complete the word equation for the complete combustion of methane.

methane + …….………….. ( ………………………… + …………………………..

6. Draw and describe the fire triangle.

7. A liquid X is made of only 2 elements. It burns to produce 2 products. One is a colourless

liquid which freezes at 0 oC and boils at 100 oC; the second turns limewater a milky colour.

a) Name the 2 products.

b) Name the 2 elements present in element X.

c) What type of substance is liquid X?

8. A hydrocarbon is burnt is a limited amount of oxygen.

a) Which harmful gas is produced?

b) How does this gas harm the body?

9. When fossil fuels burn, they produce carbon dioxide.

a) Name and describe the environmental issue linked to carbon dioxide in the

atmosphere.

b) Describe a method of reducing the amount of carbon dioxide emitted into the

atmosphere.

10. When coal is burned, the acidic gas sulphur dioxide is produced.

a) What element must be present in the coal?

b) What environmental problem is caused by sulphur dioxide being released into the

atmosphere?

11. Read the following information about biofuels and then answer the questions below.

Biofuels are fuels made from any kind of plant or animal material. Even waste material, such as used oil from fast-food restaurants, can make biofuels.

Ethanol is one example of a biofuel. Ethanol is made from grain crops, such as corn. Like most biofuels, it is used to replace gasoline and diesel fuels.

Biofuels may contribute less to global warming than other fuels. Both biofuels and fossil fuels release carbon dioxide when burned. However, crops grown for biofuels also remove carbon dioxide from the air as they grow.

a) What raw materials can be used to make biofuels?

b) Why are biofuel crops a renewable energy resource?

c) How does the use of biofuels affect the cost of food?

d) List two possible sources of biofuels.

e) What is the primary use of biofuels?

12. Hydrogen gas can be used as an alternative fuel.

a) Give one advantage of using hydrogen as a fuel for cars over petrol.

b) Give one disadvantage of using hydrogen as a fuel.

13. The diagram represents the carbon cycle.

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a) Name the processes X and Y in the carbon cycle.

b) Name another process which releases carbon dioxide into the atmosphere.

14. Copy out the sentences below and fill in the missing word(s). The answers are shown

jumbled up in brackets at the end of the question.

a) Nuclear power stations use a metal called _____________________ . (manuriu)

b) Uranium is dangerous because it can cause illnesses like _____________________ . (ccaenr)

c) Renewable energy sources will _____________________ run out. (eenvr)

d) Solar cells turn energy from the Sun directly into _____________________ . (eelcitycrit)

e) A _____________________ can be powered by a solar cell. (torulacalc)

f) Solar panels can be used to provide _____________________ _____________________ to

homes. (oht wrate)

g) A biomass fuel is one made from _____________________ and _____________________

and their waste. (stnpla, slaanim)

h) Wood is an example of a _____________________ fuel. (miaboss)

15. Which of the following energy sources which do not rely on the Sun:

coal nuclear power hydroelectric power tidal power

biomass oil geothermal

Hydrocarbons

1. What is meant by a ‘hydrocarbon’?

2. Crude oil is a mixture of chemical compounds. Before the compounds can be used, the crude oil must be separated into fractions. Use the diagram opposite to describe how crude oil is separated into its fractions.

3. Give the meaning of the following words.

a) flammable

b) viscous

c) fractional distillation

4. The following questions refer to properties of fractions, collected over the temperature

ranges shown:

|Fraction |Temperature range (0C) |

|1 | ................
................

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