Using resources

Question 1

What do humans use the earth’s resources for?

Answer 1

Warmth, shelter food and transport.

Question 2

What is meant by finite and infinite resources?

Answer 2

Finite- Limited
Infinite- Unlimited, replaced faster than used up.

Question 3

What is chemistry responsible for in agriculture?

Answer 3

Improving industrial processes + creating sustainable methods of distributing products.

Question 4

Give examples of how chemistry has replaced natural products for synthetic ones.

Answer 4

Rubber- extracted from tree sap (latex), now: rubber-like polymer.
Fertilizers- Enhance growth of plants.

Question 5

What is…
renewable?
non-renewable?

Answer 5

Renewable- Infinite e.g. timber
Non-renewable- finite, used faster than replaced.

Question 6

What is potable water?

Answer 6

Water that’s been processed + safe to drink.

Question 7

What’s the difference between pure and potable water?

Answer 7

Pure- Solely H2O molecules
Potable- May contain small amounts of minerals.

Question 8

What are the characteristics of potable water?

Answer 8

1- pH between 6.5 and 8.5
2- Limited amount of dissolved substances
3- Free of microbes

Question 9

When is water considered fresh?

Answer 9

When its relatively free from dissolved substances

Question 10

Where can water be collected from?

Answer 10

reservoirs, lakes and rivers (surface water) and aquifers (rocks storing water underground)= groundwater

Question 11

How is potable water produced?

Answer 11

• Choosing source of freshwater
• Sedimentation: pass through filter beds
• Sterilizing: using chlorine, ozone, or ultraviolet light to remove microbes.

Question 12

What is desalination?

Answer 12

Removing salt from salty water, could be done by distillation or reverse osmosis, require lots of energy so expensive.

Question 13

Describe the method of RP8, analyzing water samples.

Answer 13

universal indicator to measure pH, weigh basin and add 25cm3 Water sample A, heat on tripod/gauze under Bunsen burner until water evaporates, weigh cooled basin + calc mass of solids, do same for sample B

Question 14

Describe the method of RP8, purifying water samples.

Answer 14

Add water sample to conical flask+ set up apparatus for distillation, heat using Bunsen burner until boiling occurs, reduce the heat so that the water boils gently for some time, distilled water will collect in cooled test tube, analyze the water by determining its boiling point

Question 15

What are the sources of waste water?

Answer 15

Domestic (passes into sewers), agricultural waste (farms/nutrient run-off) and industrial

Question 16

What needs to be done to sewage and agricultural waste water during treatment?

Answer 16

Organic matter + microbes need to be removed, otherwise it could pose serious health risks.

Question 17

What needs to be done to industrial water during treatment?

Answer 17

Removal of chemicals.

Question 18

What are the steps of treating sewage water?

Answer 18

1- Screening/grit removal
2- Sedimentation: allow heavy solids sink to form sludge and lighter solids stay on surface (effluent)
3- Effluent (organic matter) broken down by aerobic digestion
4- Sludge broken down by anaerobic digestion to form methane gas + digested waste

Question 19

What are the products of sludge broken down by anaerobic digestion and what are they used for?

Answer 19

Methane gas- energy
Digested waste- fertilisers

Question 20

What happens after sewage water treatment if there are still microbes?

Answer 20

Chemicals can be added or ultraviolet radiation

Question 21

Comment on the relative ease of
obtaining potable water from waste, ground and salt water.

Answer 21

Sewage treatment easier and cheaper than desalination, however treating fresh water is easiest.

Question 22

Explain why alternative methods of extracting metals must exist?

Answer 22

Copper is becoming more scarce, so now low grade (non-economical) ores must be extracted cheaply.

Question 23

Name the 2 ways of alternative methods of extracting metals.

Answer 23

Phytomining
Bioleaching

Question 24

Explain Phytomining.

Answer 24

Plants grown where metals are known to be in the soil, they absorb metal through roots and become concentrated in roots and shoots. They are dried and burned and the ash must go through electrolysis or displacement to get the metal.

Question 25

Explain bioleaching.

Answer 25

Some bacteria can break down ores into acidic solutions (leachate), acidic solution must go through electrolysis or displacement reaction. Produces toxic chemicals.

Question 26

State the pros and cons of the alternative methods of extracting metals.

Answer 26

Pros: Avoid significant environmental damage, economical
Cons: Slow, require electrolysis/displacement reactions

Question 27

What is the life cycle assessment used for?

Answer 27

Analysis of overall environmental impact that a product has throughout its lifetime.

Question 28

What stages are assessed in LCAs?

Answer 28

Raw material extractions, Manufacturing, usage, disposal

Question 29

What’s considered in the raw material stage of LCAs?

Answer 29

Using limited/unlimited resources, damaging habitats through deforestation/mining

Question 30

What’s considered in the M+P stage of LCAs?

Answer 30

Land for factories, production of waste, transport

Question 31

What’s considered in the usage stage of LCAs?

Answer 31

How many times used, how long its used, pollution produced

Question 32

What’s considered in the disposal stage of LCAs?

Answer 32

recycled? burned? landfill?

Question 33

How are LCAs carried out?

Answer 33

Some stages quantifiable, some not = biased. Some products don’t come with a complete LCA so paint good pic of company.