Using resources

Question 1

What is sustainable development?

Answer 1

development that meets needs of current generation without compromising ability to meet the needs of future generations

Question 2

How do we use Earth’s resources?

Answer 2

• process finite resources for food, clothing, fuels
• supplemented by agriculture

Question 3

What is potable water?

Answer 3

• water that is safe to drink
• contains dissolved substances (mineral ions and gases)

Question 4

What is pure water?

Answer 4

• has no dissolved substances

Question 5

How is fresh water treated?

Answer 5

• filtration - mesh removes large contaminants, goes thorugh sand and gravel beds
• sterilisation - chlorine/ ozone bubbled through water/ UV light used to kill bacteria

Question 6

What are the sources of fresh water?

Answer 6

• ground water, water from river/ lakes

Question 7

How is salty water treated?

Answer 7

• reverse osmosis (water forced through partially permeable membrane with high pressure)
• simple distillation
• requires large amounts of energy

Question 8

How is waste water treated?

Answer 8

1) screening- removes large objects and grit
2) sedimentation produces sewage sludge and effluent
3) anaerobic digestioin of sewage sludge
4) aerobic biological treatment of effluent reduces volume of solid waste

Question 9

Why does waste water need to be treated before it is released back into the environment?

Answer 9

• filters out harmful substances and microbes
• may cause disease and damage environment

Question 10

How do you analyse a water sample?

Answer 10

1) measure pH by using universal indicator paper
2) measure and record mass of evaporating basin
3) 50g of water sample into basin
4) place basin onto tripod and gauze
5) heat with bunsen burner to evaporate all water
6) reweigh the evaporating basin, increase in mass = dissolved solids present

Question 11

How do you purify a water sample?

Answer 11

• simple distillation
• heat sample of distillate until it boils (pure water boils at 100C)