earths atmosphhere

Question 1

what is a greenhouse gas and some examples

Answer 1

a gas that contributes to the greenhouse effect by absorbing infrared radiation

• water vapor
• ozone
• CO2
• methane
• nitrous oxides

Question 2

how is methane caused

Answer 2

60% of methane is caused by humans including agriculture, animal agriculture and rice production waste

Question 3

greenhouse gases why they increase and why they decrease

Answer 3

Co2 methane and water vapor

inc: deforestation , rice fields , landfill sites , cattle and cars burning fossil fuels
dec: photosynthesis and dissolving in ocean

Question 4

what is climate change

Answer 4

describes a change in average conditions over a long period of tome

Question 5

what is carbon footprint

Answer 5

amount of co2 released into the atmosphere as a result of the activities of a particular individual organistatiob or community

Question 6

what are finite resources

Answer 6

resources that are being used up faster than they can be replaced. there is a limited amount

Question 7

what are renewable resources

Answer 7

resources thag can be replaced at same they are used up

Question 8

what is potable water

Answer 8

safe to drink should have low levels of

dissolved salts
microbes

Question 9

why is potable water not pure water

Answer 9

most drinking water contains some dissolved sales

pure wager has no dissolved salts

Question 10

rain water dissolves some gassed from air as it falls to ground. rainwater collects :

Answer 10

underground - ground wager

in lakes

in rivers

and is called ‘fresh water’

Question 11

what are sterilizing agents and what are they used for

Answer 11

chlorine
ozone
ultraviolet

used for fresh water for sterilizing (killing microbes )

Question 12

whag is desalination

Answer 12

distillation

using membranes e.g reverse osmosis

Question 13

when is desalination used

Answer 13

if fresh water supplies are limited we may hv to desalinate salty water and or sea water

Question 14

what can potable water be obtained from

Answer 14

fresh water supplies or groundwater

desalination or salty water

treatment / sewage of agricultural water

Question 15

what is sewage treatment

Answer 15

1) screening removes large solid particles like grit by passing sewage through a screen
2) sedimentation allows the small solid particles (sediment) to sink to bottom of tank forming sewage sludge white liquid (effluent ) remains above
3) sewage sludge is dried and anaerobically digested whuch removes organic matter. it produces biogas used to make electricity. dried sludge can be used as fertilizer
4) the effluent is aerobically digested. this removes organic mather and harmful microbes

Question 16

extracting copper from rich ores

Answer 16

can be removed from its ore by adding sulfuric acid to make a soluatioh before purification

OR

smelting (roasting) the ore with air to produce umpire copper

impure copper can make positive electrodes for electrolysis to make pure copper. smelting and purifying uses a lot of energy, electricity and money

Question 17

extracting copper electrolysis

Answer 17

negative copper electrode (cathode ) we get reduction Cu2+ + 2e = Cu

positive copper electrode (anode) we get oxidation Cu= Cu2+ + 2e-

ionic equation : Fe(s)+Cu2+=Fe +Cu

Question 18

bioleaching and phytomining provkems

Answer 18

mining destroys habitats
waste from mining pollutes areas
smelting realeases gasses such as So2

electrolysis uses large amounts of energy
only worthwhile extracting high grade ore

Question 19

advantages of phytomining

Answer 19

uses low grade copper ores

requires less energy than smelting

produces less air pollution

reduces amount of waste rock

Question 20

disadvantages of phytomining

Answer 20

can produce toxic chemicals

much slower process

electrolysis requires large amounts of electricity

Question 21

advantages of bioleaching

Answer 21

simple process

cheap process

we can use low grade ores

enviornmentallt friendly / fewer waste gasses produced

Question 22

disadvantages of bioleaching

Answer 22

slow process

toxic chemicals are produced

has low efficiency

Question 23

describe desalination plant

Answer 23

built to produce fresh water from salty water

distillation condensation + evaporation

cons = expensive , high energy costs and lots of water boiled, looks ugly

flash distillation invovles hugh pressures to reduce costs

reserve osmosis using membranes can also desalinate water

no heating needed but lots of pressure

Question 24

required practical : water purification

Answer 24

1. use universal indicator paper to measure PH of wager sample
2. accurately weigh any empty evaporating basin and record to two decimal places
3. pour 10cm cubed of water sample 1 into evaporating basin
4. heat evaporating basin on a tripod and gauze using a bunsen burner until the solids start to form and the majority of water has been evaporated
5. weigh the cooled evaporating basin against and calculate mass of solids that were dissolved in water
6. record results in a table

Question 25

when using electrolysis to extract copper which electrode will copper form on

Answer 25

negative cathode as copper forms cu2+ ions whuch attract to negative ion

Question 26

whag is phytomining

Answer 26

used to extract copper from low grace copper ores using plants which can absorb copper through their roots grown on copper containing soil , plants are then burnt and copper is extracted as copper is in ash

Question 27

what is bioleaching

Answer 27

bioleaching uses bacteria to feed on low grade metal ores a solution of copper ions (leachate) is produced. scrap iron and electrolysis is used to extract copper.

20% of copper comes from bioleaching it’s a slow process but important as copper ores run out

Question 28

what are the aims of the reduce reuse recycle

Answer 28

to reduce our use of limited resources

reduce our use of energy

reduce waste we produce

Question 29

stages of aluminum recycling

Answer 29

1) scrap aluminum into a feed conveyor

2) shredder
3) decoater
4) melting furnace
5) tilting holding furnace
6) filtration unit
7) direct chill casting unit
8) shredder
9) ingots

Question 30

why is recycling copper tricky

Answer 30

it is often alloyed with other metals

Question 31

what is a life cycle assessment

Answer 31

analysis of impact of a manaufactured product on eviornent

Question 32

4 main stages of a life cycle assessment

Answer 32

extracting and processing raw materials needed

manaufacturijf product and its packaging

using product during lifetime

disposing a product at end of its useful life

Question 33

manaufacture plastic bags vs paper bags

Answer 33

cheaper to make large quantities of bags from plastic

more expensive for paper as handles must be glued on

Question 34

use of plastic bag vs paper bag

Answer 34

lower impact on environment as plastic bags are usually stronger so can be reused

paper can only be reused limited number of times

Question 35

disposal of plastic bags vs paper bags

Answer 35

paper can be recycled easily and if disposed on landfill they biodegrade easily

plastic cab sometimes be collected and recycled if disposed of as litter they do not biodegrade , in landfill may take decades or centuries to degrade