Unit 2 Topic 5 Part 1

Question 1

Define hydrocarbon

Answer 1

A molecule containing hydrogen and carbon only

Question 2

Define fossil fuels

Answer 2

Fossil fuels that have formed over millions of years from dead plants and animals. Examples include coal, crude oil and natural gas.

Question 3

Is the bottom of a fractionating column hotter or colder than the top?

Answer 3

Hotter

Question 4

Which chemical is piped in at the bottom of a fractionating column?

Answer 4

Crude oil

Question 5

What happens to the size of the molecules of fractions as you move down the fractionating column?

Answer 5

They become thicker

Question 6

Define condensation

Answer 6

Change of state from a gas to a liquid on cooling

Question 7

What does LPG stand for ?

Answer 7

Liquid Petroleum Gas

Question 8

What are the main environmental concerns associated with the petrochemical industry?

Answer 8

Transport of crude oil can result in spills or leaks.
Drilling for oil in the sea bed can result in leaks.
Burning fossil fuels releases carbon dioxide, which is a greenhouse gas.

First two reasons can result in severe water pollution which harms and kills sea life.

Question 9

Which element do all fossil fuels contain?

Answer 9

Carbon

Question 10

When a fossil fuel burns, which gas does it give off?

Answer 10

Carbon dioxide

Question 11

Is wood a fossil fuel?

Answer 11

No

Question 12

True or false? Burning fossil fuels releases heat.

Answer 12

True

Question 13

In order to burn fossil fuels, what element do you need?

Answer 13

Oxygen

Question 14

Define homologous series

Answer 14

A family of organic compounds which have the same general formula and similar chemical properties, and differ by a gradual change in physical properties and a CH2 unit.

Question 15

What is the general formula for the alkanes?

Answer 15

C(n)H(2n+2) - where n is the number of carbon atoms

Question 16

What trait do all alkanes have in common?

Answer 16

They are all hydrocarbons

Question 17

Name the first four members of the alkanes.

Answer 17

Methane, Ethane, Propane, Butane

Question 18

Give the molecular formula of Methane

Answer 18

CH4

Question 19

Give the molecular formula of Ethane

Answer 19

C2H6

Question 20

Give the molecular formula of Propane

Answer 20

C3H8

Question 21

Give the molecular formula of Butane

Answer 21

C4H10

Question 22

Which state of matter are all of the alkanes at room temperature?

Answer 22

Gas

Question 23

What type of bond is present in all alkanes between all the atoms?

Answer 23

Single covalent bond

Question 24

What can we refer to the alkanes as?

Answer 24

Saturated hydrocarbons

Question 25

What do the alkanes not have, which makes them less reactive?

Answer 25

A functional group

Question 26

How can we identify a particular alkane?

Answer 26

Identify the number of carbon atoms

Question 27

Each carbon in an alkane has how many bonds?

Answer 27

4

Question 28

If the number of carbon atoms increases, what happens to the boiling point?

Answer 28

It increases

Question 29

Hydrocarbons are mainly used as what?

Answer 29

Fuels

Question 30

The burning of a substance in air

Answer 30

Combustion

Question 31

What does combustion involve the reaction of, and what does it form?

Answer 31

Oxygen with the fuel, to form oxides

Question 32

Is combustion an oxidation or reduction reaction?

Answer 32

Oxidation

Question 33

Is combustion an exothermic or endothermic reaction?

Answer 33

Exothermic

Question 34

General equation for complete combustion

Answer 34

Hydrocarbon + oxygen --> carbon dioxide + water + energy

Question 35

General equation for incomplete combustion

Answer 35

Hydrocarbon + oxygen --> carbon monoxide + water + energy

Question 36

In a combustion reaction, what kind of flame does the gas burn with?

Answer 36

The gas burns with a clear blue flame

Question 37

What is the test for carbon dioxide?

Answer 37

Bubble through limewater which will turn milky white

Question 38

Name the substance in coal gas which is toxic.

Answer 38

Carbon monoxide

Question 39

Name an energy source used to make many organic chemicals, including plastics

Answer 39

Crude oil

Question 40

Bond breaking requires energy and is ...

Answer 40

endothermic

Question 41

Bond making gives out energy and is ...

Answer 41

exothermic

Question 42

The alkenes are all ...

Answer 42

hydrocarbons

Question 43

Give the molecular formula of ethene

Answer 43

C2H4

Question 44

Give the molecular formula of propene

Answer 44

C3H6

Question 45

General formula of the alkenes

Answer 45

C(n)H(2n)

Question 46

Alkenes must have at least one of these between two of the carbon atoms

Answer 46

Double covalent bond

Question 47

Alkenes can be described as ...

Answer 47

unsaturated hydrocarbons

Question 48

Unsaturated

Answer 48

Refers to compounds with a double bond

Question 49

Saturated

Answer 49

Refers to compounds without a double bond

Question 50

What can alkenes be used to make?

Answer 50

Polymers

Question 51

Each alkene has how many bonds around each carbon atom?

Answer 51

4

Question 52

How can we distinguish an alkane from an alkene?

Answer 52

Shake the hydrocarbon with bromine water (brown solution)

Question 53

What does the bromine do when shook with an alkene?

Answer 53

The bromine adds across the double bond of the alkene to produce a halogenoalkane.

Question 54

Observation after shaking an alkane with bromine water

Answer 54

Stays orange

Question 55

Observation after shaking an alkene with bromine water

Answer 55

Turns from orange to colourless

Question 56

What state are ethene and propene at room temperature?

Answer 56

Gas

Question 57

Why is there no member of the alkenes with just one carbon atom in the molecule?

Answer 57

Alkenes are unsaturated hydrocarbons which means there must be a double bond. A double bond can't exist between carbon and hydrogen, only between two carbons.

Question 58

How are different fuels separated from each other by fractional distillation?

Answer 58

Boiling points and the number of carbon atoms in each molecule

Question 59

Name two chemicals that ethene can be used in the manufacture of.

Answer 59

Polythene and ethanol

Question 60

Ethene may be burned as a ...

Answer 60

fuel

Question 61

Give two uses of polythene

Answer 61

Plastic bags and cling film

Question 62

Name three products obtained from crude oil

Answer 62

Petrol, kerosine and refinery gas

Question 63

Renewable resources

Answer 63

Renewable resources are continuously supplied by nature as they are used by consumers.

Question 64

Give two examples of renewable resources

Answer 64

Wind and solar energy

Question 65

Non-renewable resources

Answer 65

Fuels that are finite and can't be replaced once they are used up

Question 66

What are chemicals obtained from crude oil known as?

Answer 66

Hydrocarbons

Question 67

Briefly describe crude oil

Answer 67

Crude oil is a liquid mixture of hydrocarbons which includes dissolved gases and solids

Question 68

Give the names of three fractions obtained from a fractionating column after crude oil is piped into the bottom

Answer 68

Petrol/gasoline, bitumen and refinery gas

Question 69

Use of refinery gas

Answer 69

Fuel for gas ovens

Question 70

Use of petrol

Answer 70

Fuel for vehicles

Question 71

Use of kerosine

Answer 71

Jet engines

Question 72

Use of diesel oils

Answer 72

In diesel engines

Question 73

Use of fuel oil

Answer 73

Fuel for ships

Question 74

Use of lubricating oil

Answer 74

Lubricants

Question 75

Use of tar (bitumen)

Answer 75

Asphalt on roads

Question 76

Describe the separation of crude oil by fractional distillation

Answer 76

Heated crude oil is piped in at the bottom of the fractionating column. Crude oil is heated to cause continual evaporation followed by condensation. Various fractions are tapped off at different levels where they condense.

Question 77

What is the functional group of a molecule?

Answer 77

The reactive group of the molecule

Question 78

Natural gas is mainly ...

Answer 78

Methane

Question 79

Bottled gas is ...

Answer 79

Propane/butane

Question 80

An experiment to distinguish between cyclohexane and cyclohexene (determining the presence of a C=C bond)

Answer 80

1. Measure out 2cm3 of cyclohexane and put it into a labelled test tube. 2. Measure out 2cm3 of cyclohexene and put it into a labelled test tube. 3. Add 1cm3 of bromine water to each test tube and using a bung, shake both 4. Write down your observations.

Question 81

Results of experiment to distinguish cyclohexane from cyclohexene.

Answer 81

Cyclohexane - bromine water stays orange | Cyclohexene - bromine water changes from orange to colourless

Question 82

General formula of the alcohols

Answer 82

C(n)H(2n+1)OH

Question 83

General formula of carboxylic acids

Answer 83

C(n)H(2n+1)COOH

Question 84

Why is it important to make the extraction of crude oil more efficient?

Answer 84

World reserves of crude oil are running out fast, and crude oil provides to us a wide range of useful substances that we cannot do without.