earths reasources

Question 1

whats a finite resource

Answer 1

something thats used up at a greater speed than it can be produced, usually natural made reasoruces

Question 2

exaamples of finite reasoruces

Answer 2

limestone from hydrocarbons for builings
metal ores for mela extraction
crude oil for polymers and fuel

Question 3

example of ethanol as a reneable resrouce

Answer 3

currently we use the hydrocarbon of ethene as a polymer/ fuel but we can use ethanol, made as a sugar plant

Question 4

renewable reasources example

Answer 4

wood chips to be combusted at power stations
biofuels from recently dead plants
wave, hydroelectric, wind and solar fuel

Question 5

what is potable water

Answer 5

water thats fit to drink

Question 6

reasons water can become unclean

Answer 6

contains minerals from soil and ground
contains dissolved salts from oceans
dissolves and absorbs gases from the air as its precipitated

Question 7

main steps of filtering water

Answer 7

passed through a crosshatched screen that collects any extremely large peices through filtration
sand and soil settle at the bottom
aliminium sulphate is added to the water making soluable solids clump together and collect as sludge/ mud for landfil with water at the top
chlorine is added to the clean water to make sure all bacteria is killed and then the ph is corrected incase of acidity

Question 8

whats flash distillation

Answer 8

usually frac distillation to separate water works but is v expensive, here it can be done cheaper by using a lower pressure so that the water boils below 100c

Question 9

what is desalination

Answer 9

converting salty water to pure, used in island countries and oil rich nations/deserts

Question 10

whats reverse osmosis

Answer 10

using membranes to separate water and salt by membranes which remove the dissolves salt
no heating so less energy required than disstilation but is needed to pressurose the water

Question 11

four main steps of sewage treatment and reasoning

Answer 11

screening
primary treatment
secondary treatment
final treatment
sewage has to be safe before it can be returned to the enviroment from toxins and bacteria etc

Question 12

screening- sewage treatment- explained

Answer 12

like water treatment pass it througha metal grid to trap anything v large

Question 13

primary stage- sewage treatment

Answer 13

solid sediments like sand can settle out and as sludge is pushed to the bottom where its piped out

Question 14

secondary stage- sewage treatment

Answer 14

the water is now free of visable sludge but now bacteria feeds and decomposes any remaining microorganisms aerobically

Question 15

final stage- sewage treatment

Answer 15

the water can go back to rivers
if needed it can be sterolised by chlorine/ ultraviolent radiation but then it may harm the ennviroment or need its ph altered

Question 16

where does the bacteria go from the secondary stage

Answer 16

settles at the bottom of the tank, if its still a useful decomposer its recycled back to that stage or if not it can go with the sludge

Question 17

uses of sludge after discarding in the prim treatment

Answer 17

it can be dried as fertiliser
it can form a biogas for renewable combustion
an be dried out to form a solid that can be combusted for electricity

Question 18

four factors of a life cycle assesment

Answer 18

how the materials were sourced
how they were disposed of
how the product was used
how it was made

Question 19

why to recycle alluminium

Answer 19

to requires HUGE amounts of energy to extract using electrolysis
recycling does not need to be extracted so mass saves energy

Question 20

why recycle iron and steel

Answer 20

it is double the energy to extract iron and turn it to steel, mostly through combustion of finite reasources heating the iron in blast furnaces

Question 21

enviromental impacts of mining ores rather than recycling

Answer 21

pollution arises from quarrying/ combustion
huge pits for mining scar the landscape
rain draining through exposed ores can become acidic slag heaps

Question 22

limitations of LCA

Answer 22

its hard to find the data for each step for every product
companies can alter their LCA or lie to seem favourable
its hard to compare differnet harms eg climate change vs lung disease

Question 23

criteria for potable water

Answer 23

no microorgansims
ph level between 6.5-8.5
level of soluable substances has to be kept low

Question 24

test for water

Answer 24

anhydrous copper sulphate turns blue