C13 & C14 mocks revision
what made up the old atmosphere
4% water vapour, 95% carbon dioxide and 1% nitrogen+ammonia+methane
what makes up the modern atmosphere
80% Nitrogen, 20% Oxygen, trace amounts of other gasses
How was the atmosphere formed (4points)
1. extreme amounts of volcanic activity released water vapour and nitrogen into the air
2. the water vapour condensed and formed oceans
3. nitrogen didn't reduce because it was unreactive
4.plants began to photosynthesise, taking in carbon dioxide and producing oxygen
define ore
a naturally occuring rock that contains metal or a metal compound
what metals are extracted through electrolysis
anything more reactive than carbon (Potassium, Sodium, Calcium, Magnesium, Aluminium)
What metals are extracted through displacement
anything less reactive than carbon (Zinc, Iron, Tin, Lead)
What metals are found in their raw form (not in ore)
Anything less reactive than hydrogen (Copper, Silver, Gold)
Explain electrolysis (3points)
1. the ore is converted into a liquid state through melting or dissolving
2. ions can then move freely and an electrical current can be passed through
3. the current seperates the pure metal
what greenhouse gasses are in our atmosphere
water vapour, carbon dioxide and methane
explain the greenhouse effect (6steps)
1. electromagnetic radiation enters the atmosphere
2. earth absorbs most of it and warms up
3. earth radiates infared radiation
4.msome goes to space
5. some is absorbed by greenhouse gases
6. the lower atmosphere warms up
define finite resources
resources that can run out because they are being used faster than they can be replaced
define renewable resources
resources that can be replaced faster or at the same rate they are used so they wont run out
define sustainability
meeting the needs of society today without endangering future generations
explain fractional distilation
a mixture is distilled and the evaporated components are collected as they condense at different temperatures
How are fertilisers synthetically produced
nitrogen in the air is used in the haber process where nitrogen and hydrogen are reacted to produce ammonia
define climate
the average temperature and weather cycles over decades of time
why is global warming different from climate change
the climate has always changed naturally but global warming is caused by human activities
4 effects of climate change
-polar ice and glaciers melting
-sea levels rising
-rainfall patterns changing
-habitiats changing
define potsable water
water safe for human consumption
requiremets for potable water
low levels of salt and microbes
how is potable water made from fresh spring water
the water is passed through filter beds and then steralised with either chlorine, ozone or ultraviolet light
How is potable water made from sea water (2points)
1. distilation, boiling sea water allows the salt to remain in the liquid while the steam is pure water which can be condensed to make potable water.
2. reverse osmosis, pushing water through a membrane under high pressure filters out most ions and molecules
what source is ideal for making potable water
fresh water springs not sea water
how is sewage treated to return to the enviroment (4steps)
1. screening and grit removal to remove large particles
2. sedimantation allows tiny particles to seperate from the effluent and form a sludge
3. the sludge is digested by bacteria
4. the effluent is treated with bacteria to reduce the volume of solid waste
what is a life cycle assessment (LCA)
a start to finish analysis of a manufactured product on the enviroment
what are the main stages of an LCA and what do they include
1. extracting and processing materials
2.manufacture
3. use of the product
4. disposal
it includes information about energy use, transport of goods and release of waster for each stage
what is the purpose of a comparative LCA
to determine which products would have a lower negative impact on the enviroment
4 advantages of recycling
1. fewer mines
2. less crude oil extraction
3. less energy therefore less greenhouse gases
4. less waste in landfill
3 disadvantages of recycling
1.transportation transportation organisation ,wrokers, fuel and vehicles
2. it can be hard to sort metals
3. sorted metals need to be transported to make ingots
what are the aims of the treating water required practical
1. analyse water samples from different sources in terms of PH and dissolved solids
2. distil sea water
How do you analyse water samples in terms of PH and dissolved solids (4steps)
1. test the PH of each sample with indicator papr
2. weigh the evaporating basin and put 50cm3 of the sample on it
3. heat it over a bunsen until no liquid remains
4. weigh the evaporating basin again and calculate the mass of dissolved solids
how are atmospheric pollutants produced
when fossil fuels are burned
dangers of sulfur dioxide
oxidies furthur in the atmosphere into sulfur trioxide which dissolves in rain water causing acid rain
dangers of NOx gases
can cause cid rain or smog, which leads to asthma attacks or even death