topic 10 - using resources Flashcards
what are ceramics
non metal solids with high metling points
properties clay ceramics
- soft when dug from ground so can be moulded
- hardens when fired at high temps
properties and types glass ceramics
- moulded when hot
- brittle (break easily)
- transparent
- soda-lime glass - made from limestone, sand and sodium carbonate
- borosilicate glass has a higher melting point then soda-lime glass
what are composites
made from one material embedded into another
fibrs or fragmented are surrounded by a matrix
4 types of composites
- fibreglass - glass em,bedded in matrix of polymer, low density, very strong, boats/surfboards
- carbon fibre - nano tubes with a polymer matrix, strong and light
- concrete - aggregate embedded in cement, very strong
- wood - cellulose fibres embedded by organic polymer matrix
low density poly(ethene) LDPE and
high density poly(ethene) HDPE
- LDPE made at modeate tempuratures and high pressure, flexible (bags)
- HDPE made at low temp and low pressure with catalyst, rigid (drainpipes)
thermosoftening polymers and thermosetting polymers
- thermoSOFTENING - weak forces between chains/melt and remould
- thermoSETTING - cross links, solid structure, don’t soften when heated, hard and rigid.
equation for rust
iron+oxygen+water–>hydrated iron(III) oxide (rust)
what is corrosion
when metals react with substances in their environment and are gradually destroyed
what happens to ALUMINION when it corrodes compared to iron
- when aluminium oxide corrodes it doesn’t flake away but forms a protective layer that sticks to the aluminion and stops a further reaction
what is needed for iron to rust
air and water
barrier method of preventing rust
- painting
- oiling/ greasing
- electroplating
sacrificial method of preventing rust
- more reactive metal (eg zinc or magnesium) an the water and oxygen will react with this instead
definition of a finite and renewable energy resource
FINITE
- being used up at a faster rate than replaced
RENEWABLE
- formed at same of faster rate then used
how can copper be used more efficently
- extracting low-grade copper from its ore (bc its finite) through BIOLEACHING and PHYTOMINING which are less damaging to the environment but very slow.
4 main stages of a LIFE CYCLE ASSESMENT
- GET RAW MATERIALS - extracting could damage environment or need energy - polluting
- MAUFACTURE AND PACKAGE - energy pollution, waste?
- USING - buring fuels?, how long its used for
- DISPOSAL - landfill?, transport?, burning- pollution?
problems with life cycle assesments
- hard to say what has a worse effect - subjective
- bias - companies
- finding the effects of some pollutants isn’t easily quantified
what is potable water
- treated water safe for humans to drink
- not pure because it does contain other dissolved substances
- pH levels between 6.5 and 8.5
- not contain any microorganisms
where can fresh water be found in the uk
surface water - rivers, lakes, resiviours
groundwater - aquifers
how to treat fresh water
- FILTRATION - wire mesh for large bits and gravel and sand for small bits
- STERILISATION - bubbling chlorine, ozone, ultraviolet light.
how do dry countries get water
treating seawater with DESALINATION which is the removal of salt from seawater by
- distillation
- reverse osmosis (very expensive bc a lot of energy)
potable water distillation PRACTICLE
- test pH of water and neutralise it using titration
- test water for the presence of SODIUM CHLORIDE
- to distill water pour salty water into distillation apparatus
- heat flask so water boils leaving dissolved salts in flask
- steam will condense back into liquid and collect.
examples of domestic, agriculture and industrial water waste
- domestic - showers, toilets, washing up, has to be treated to remove organic matter and harmful microbes before it can be put back into rivers
- agricultural - nutrients run off, has to be treated to remove organic matter and harmful microbes before it can be put back into rivers
- industrial - factory waste and Haber porcess
sewage treatment stages
- SCREENING - removes large bits
- SEDIMENTATION STAND IN SETTLEMENT TANK - heavier bits sink bottom = SLUDGE whilist lighter EFFLUENT floats on top
- EFFlUENT removed and treated by AEROBIC DIGESTION (air pumped through to break down organic matter)
- SLUDGE broken down by ANAEROBIC DIGESTION which breaks down organic matter and releases METHANE
word equation for the HABER PROCESS
nitrogen + hydrogen <–> ammonia + (heat)
conditions of the haber process
- 450 degrees Celsius COMPROMISE - because at low temps there would be a slower rate of reaction but a high temps the equilibrium will move the wrong way
- 200 atm - because high pressure maximises % yield and increases rate of reaction but too high would be too ££ and too dangerous.
- iron catalyst - makes reaction faster but doesn’t effect the yield
what do NPK fertilisers contain
formulations containing:
N - nitrogen for leaf development
P - phosphorous for root and flower growth
K - potassium for overall health and disease resistance
why do we need NPK fertilisers
- nutrients for plants to grow
- the elements may be missing from soil but previous plant
- increase crop yield and grow bigger and faster.
equations for the reaction of ammonium nitrate
ammonia + nitric acid –> ammonium nitrate (NH4NO)
chemical equation for the HABER PROCESS
N2 + 3H2 <–> 2NH3
high carbon steel
strong but brittle
low carbon steel
softer and easily shaped
stainless steel
hard and resistant to corrosion
