Chapter 10 - Using Resources

Question 1

What are the four key things humans use resources for?

Answer 1

• Warmth
• Shelter
• Food
• Transport

Question 2

Where do resources come from?

Answer 2

Often from agriculture e.g. cotton from plants
Chemistry sometimes can provide a synthetic alternative that replace natural resources e.g. produce rubber from crude oil instead of getting it from the sap of a tree

Question 3

What does sustainable mean?

Answer 3

We can meet our needs without preventing future generations from being able to meet theirs

Question 4

What is pure water?

Answer 4

Water with no dissolved substances

Question 5

What is potable water?

Answer 5

Water that is safe to drink (contains low levels of dissolved substances)

Question 6

How to we produce potable water from fresh water?

Answer 6

1. Find fresh water source e.g. river
2. Pass through filter bed to remove leaves and suspended particles
3. Sterilise to kill microbes using chlorine (or ozone or UV light)

Question 7

What is the process called to get potable water from salty water?

Answer 7

Desalination

Question 8

What are the two types of desalination?

Answer 8

• Distillation

- Reverse osmosis

Question 9

What are the downsides to desalination?

Answer 9

Both methods require a lot of energy so are very expensive

Question 10

How do you analyse if water is pure?

Answer 10

1. Check pH by placing small amount of water onto universal indicator paper. If it turns green, pH = 7 and the water could be pure
2. Test for solids (dissolved substances) - record weight of empty evaporating basin, then weigh with water. Evaporate water using a bunsen burner. Weigh basin again. If weight is higher than the weight of the empty basin then it is impure.

Question 11

How do you purify water by distillation?

Answer 11

1. Heat water until it evaporates and forms steam
2. Steam travels along delivery tube and condenses in cold test tube
3. This is distilled/pure water

Question 12

What equipment is needed to purify water by distillation?

Answer 12

• Bunsen burner
• Tripod
• Gauze
• Conical flask
• Bung attached to delivery tube
• Test tube in ice bath (beaker filled with water and ice)

Question 13

What is produced/what is the digested sludge used for?

Answer 13

• Biogas produced during digestion

- Digested sludge = fertiliser

Question 14

Water is also used in industries e.g. to make paper and chemicals. What needs to be done before the waste water can go through general sewage treatment?

Answer 14

Harmful chemicals need to be removed

Question 15

What is the easiest way to produce potable water?

Answer 15

Use ground water from aquifiers - usually safe once traeted with chlorine

Question 16

Why are aquifiers sometimes not a safe source for potable water.

Answer 16

Can be polluted by things such as fertiliser. This means the water needs to be tested

Question 17

Why is general sewage treatment only used for potable water when water is scarce?

Answer 17

There are so many steps so it is a long process

Question 18

What is the easiest way to produce potable water?

Answer 18

Use ground water from aquifiers - usually safe once treated with chlorine

Question 19

What is the usual method to extract metal?

Answer 19

Mining metal ores

Question 20

Metals ores are running out. What are we going to have to use instead?

Answer 20

Low-grade ores

Question 21

What is phytomining?

Answer 21

1. Plants grown on land containing metal compound we want
2. Plants absorb the compound
3. The plants are harvested and burned, which produces an ash that contains a relatively high concentration of the metal compound

Question 22

What is bioleaching?

Answer 22

1. Bacteria is mixed with the low-grade ore
2. The bacteria carry out chemical reactions and produce a solution called leachate
3. The leachate contains the desired compound

Question 23

After phytomining or bioleaching, how do we extract the metal from the metal compound?

Answer 23

Using displacement reactions or electrolysis

Question 24

What is the aim of a life-cycle assessment?

Answer 24

It attempts to put a number on the environmental impact of a product

Question 25

What stages make up a life-cycle assessment?

Answer 25

1. Assess impact of extracting and processing the raw materials - how much energy is needed and are there any harmful waste products produced
2. Assess the environmental impact if the product during its lifetime
3. Disposal of products - energy required to dispose of harmful chemicals or transportation to landfill/recycling centre

Question 26

What are the issues with life-cycle assessments?

Answer 26

• can’t always be certain how environmentally damaging something is so have to make estimations which aren’t always accurate
• can be biased to support advertisers’ best interests

Question 27

Life-cycle assessment of a plastic bag

Answer 27

• made using chemicals from crude oil = non-renewable and extraction can be harmful to habitats
• needs to be chemically processed = lot of energy and waste products
• reusable and strong
• transportation to landfill
• non-biodegradable

Question 28

Life-cycle assessment of a paper bag

Answer 28

• made using wood from trees = renewable but destructive to habitats
• production of paper requires a lot of water
• needs to be chemically processed = lot of energy and waste products
• one-time use as not strong
• transportation to recycling centre (heavier than plastic bags = more energy)
• biodegradable

Question 29

Why is recycling important?

Answer 29

• Helps save limited resources and energy
• Reduces waste produced
• Reduces harm to environment

Question 30

How is glass recycled?

Answer 30

• Products like glass bottles can easily be reused for the same use
• They can be crushed/melted to make different glass products

Question 31

How is metal recycled?

Answer 31

• It is melted and then recast into different products

- Metals usually need to be separated before