Year 9 Environmental Chemistry - Revision List

Question 1

What is meant by the term atmosphere?

Answer 1

Mixture of gases surrounding a planet

Question 2

What is the proportion of nitrogen in the atmosphere?

Answer 2

Around 80%

Question 3

What is the proportion of oxygen in the atmosphere?

Answer 3

Around 20%

Question 4

What gases are present in the atmosphere in very small proportions?

Answer 4

Water vapour, noble gases, carbon dioxide

Question 5

How has the percentage of carbon dioxide changed from the early atmosphere?

Answer 5

decreased

Question 6

How has the percentage of oxygen changed from the early atmosphere?

Answer 6

increased

Question 7

How has the percentage of nitrogen changed from the early atmosphere?

Answer 7

increased

Question 8

Why did oxygen levels in the atmosphere increase?

Answer 8

photosynthesis

Question 9

What two groups of living things caused oxygen levels in the atmosphere to increase?

Answer 9

algae and plants

Question 10

Give two ways in which nitrogen levels in the early atmosphere increased?

Answer 10

Volcanoes, oxidation of ammonia

Question 11

Give three reasons why carbon dioxide levels in the early atmosphere decreased?

Answer 11

Photosynthesis, dissolving in oceans, formation of sedimentary rocks and fossil fuels

Question 12

What are greenhouse gases?

Answer 12

Gases in the atmosphere that can absorb infrared radiation (heat)

Question 13

What are the three main greenhouse gases?

Answer 13

Carbon dioxide, water vapour and methane

Question 14

What is meant by the term greenhouse effect?

Answer 14

“Trapping” of thermal energy within the atmosphere

Question 15

Why is the greenhouse effect important?

Answer 15

Maintains global temperatures high enough for life

Question 16

What is global climate change?

Answer 16

Changes in the Earth’s weather patterns due to increased concentration of greenhouse gases

Question 17

What are four potential effects of global climate change?

Answer 17

Increased global mean temperature, melting polar ice caps, rising sea levels, more frequent extreme weather events

Question 18

What is meant by the term carbon footprint?

Answer 18

Total amount of greenhouse gases emitted over the life cycle of a product, service or event

Question 19

How can the carbon footprint be reduced?

Answer 19

Reducing emissions of carbon dioxide and methane

Question 20

What is complete combustion?

Answer 20

When a fuel burns in plenty of oxygen

Question 21

What are the products of the complete combustion of hydrocarbons?

Answer 21

Carbon dioxide and water

Question 22

What do we use to test for the presence of water?

Answer 22

Cobalt chloride paper

Question 23

What change is observed to cobalt chloride paper if water is present?

Answer 23

Blue to pink

Question 24

What do we use to test for the presence of carbon dioxide?

Answer 24

Bubble through limewater

Question 25

What change is observed to limewater if carbon dioxide is present?

Answer 25

turns cloudy

Question 26

What is incomplete combustion?

Answer 26

When a fuel burns in a limited supply of oxygen

Question 27

What are the possible products of incomplete combustion of a hydrocarbon?

Answer 27

Carbon dioxide, carbon monoxide, carbon (soot) and water

Question 28

Which pollutants may be released into the atmosphere when a fuel burns?

Answer 28

Carbon dioxide, carbon monoxide, particulates, sulfur dioxide, oxides of nitrogen

Question 29

Why is carbon monoxide an environmental concern?

Answer 29

toxic

Question 30

Why is carbon monoxide difficult to detect?

Answer 30

colourless and odourless

Question 31

What environmental problem is caused by particulates?

Answer 31

global dimming

Question 32

What health problem in caused by sulfur dioxide and oxides of nitrogen?

Answer 32

respiratory problems

Question 33

What is crude oil?

Answer 33

A fossil fuel formed from ancient plankton buried in mud

Question 34

What does crude oil consist of?

Answer 34

A mixture of hydrocarbons with different carbon chain lengths

Question 35

Where is crude oil found?

Answer 35

In underground reservoirs

Question 36

How is crude oil formed?

Answer 36

High temperature and pressure over millions of years

Question 37

What is meant by the term fraction?

Answer 37

A portion of crude oil in which the hydrocarbons have a similar number of carbon atoms

Question 38

What is the first step in fractional distillation in industry?

Answer 38

vaporisation

Question 39

What is the temperature gradient in the fractionating column?

Answer 39

cooler near the top

Question 40

How are the fractions of crude oil separated?

Answer 40

according to their boiling temperature

Question 41

How is each fraction removed from the fractionating column?

Answer 41

by condensation

Question 42

Give the names of 5 useful fuels extracted from crude oil

Answer 42

Petrol, diesel, kerosene, heavy fuel oil and liquified petroleum gas (LPG)

Question 43

Give the names of 4 useful products obtained from crude oil

Answer 43

Solvents, lubricants, polymers (plastics), detergents

Question 44

How does number of carbon atoms (chain length) affect flammability of fractions of crude oil?

Answer 44

Higher chain length = lower flammability

Question 45

How does number of carbon atoms (chain length) affect viscosity of fractions of crude oil?

Answer 45

Higher chain length = higher viscosity

Question 46

How does number of carbon atoms (chain length) affect boiling point of fractions of crude oil?

Answer 46

Higher chain length = higher boiling point