earths atmosphhere Flashcards
what is a greenhouse gas and some examples
a gas that contributes to the greenhouse effect by absorbing infrared radiation
- water vapor
- ozone
- CO2
- methane
- nitrous oxides
how is methane caused
60% of methane is caused by humans including agriculture, animal agriculture and rice production waste
greenhouse gases why they increase and why they decrease
Co2 methane and water vapor
inc: deforestation , rice fields , landfill sites , cattle and cars burning fossil fuels
dec: photosynthesis and dissolving in ocean
what is climate change
describes a change in average conditions over a long period of tome
what is carbon footprint
amount of co2 released into the atmosphere as a result of the activities of a particular individual organistatiob or community
what are finite resources
resources that are being used up faster than they can be replaced. there is a limited amount
what are renewable resources
resources thag can be replaced at same they are used up
what is potable water
safe to drink should have low levels of
dissolved salts
microbes
why is potable water not pure water
most drinking water contains some dissolved sales
pure wager has no dissolved salts
rain water dissolves some gassed from air as it falls to ground. rainwater collects :
underground - ground wager
in lakes
in rivers
and is called ‘fresh water’
what are sterilizing agents and what are they used for
chlorine
ozone
ultraviolet
used for fresh water for sterilizing (killing microbes )
whag is desalination
distillation
using membranes e.g reverse osmosis
when is desalination used
if fresh water supplies are limited we may hv to desalinate salty water and or sea water
what can potable water be obtained from
fresh water supplies or groundwater
desalination or salty water
treatment / sewage of agricultural water
what is sewage treatment
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
extracting copper from rich ores
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
extracting copper electrolysis
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
bioleaching and phytomining provkems
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
advantages of phytomining
uses low grade copper ores
requires less energy than smelting
produces less air pollution
reduces amount of waste rock
disadvantages of phytomining
can produce toxic chemicals
much slower process
electrolysis requires large amounts of electricity
advantages of bioleaching
simple process
cheap process
we can use low grade ores
enviornmentallt friendly / fewer waste gasses produced
disadvantages of bioleaching
slow process
toxic chemicals are produced
has low efficiency
describe desalination plant
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
required practical : water purification
- use universal indicator paper to measure PH of wager sample
- accurately weigh any empty evaporating basin and record to two decimal places
- pour 10cm cubed of water sample 1 into evaporating basin
- 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
- weigh the cooled evaporating basin against and calculate mass of solids that were dissolved in water
- record results in a table
