CHEMISTRY C10: USING RESOURCES

Question 1

how to make water potable?

Answer 1

-reduce the concentrations of dissolved minerals and salts found in the water
- we don’t completely eradicate all the minerals and salts found in the water to

Question 2

what does potable water have low concentrations of?

Answer 2

microbes and dissolved salts

Question 3

how can be potable water be obtained?

Answer 3

-fresh water only needs filtering and sterilising; easiest to treat
-seawater is the most expensive due to the large amount of energy needed to desalinate
-waste water requires less energy than seawater but involves many steps

Question 4

what type of water is safe for human consumption?

Answer 4

potable water - it doesn’t have to chemically pure

Question 5

what do we have to do to avoid pollution?

Answer 5

treat waste water before releasing it into the environment

Question 6

what are the 3 main sources of waste water?

Answer 6

-industry, needed as some waters contain harmful chemicals
-agriculture, run-off and slurry are the main agricultural waste waters
-domestic, treatments remove the organic matter and harmful microbes found in this waste

Question 7

what does the sewage treatment include?

Answer 7

screening - removes grit and large items such as plastic bags
sedimentation - separation of sewage into heavier sludge and lighter effluent
sludge is anaerobically digested and effluent is aerobically digested

Question 8

what do Life Cycle Assessments do?

Answer 8

they asses every stage of a products life time in order to evaluate total environmental costs

Question 9

what are the 4 stages in LCA’s?

Answer 9

-acquiring raw materials
-manufacturing and packaging
-product use
-product disposal

Question 10

what is more harmful?

Answer 10

by examining a paper bag’s life cycle it is shown that they can be more damaging. the manufacturing requires more energy and they have a shorter lifespan