C10: Using Resources Flashcards
What are resources needed for?
-Warmth
-Shelter
-Food
-Transport
What are examples of natural resources?
-Food
-Wood for building
-Fuels for burning, energy
-Materials for fabrics/clothing e.g. silk, cotton
Define sustainability
Using natural materials in a way that does not compromise future generations ability to do the same
What is potable water?
Water that has low enough levels of dissolved salts & microbes that it is safe to drink
What is the most effective way of obtaining potable water?
By taking it from a freshwater source e.g. river, as this will have very little salt dissolved in it
It’s then filtered to remove large insoluble particles, then sterilised using chlorine, ozone or UV
What is desalination?
The removal of salt (e.g. from seawater) by distillation or reverse osmosis so it is safe to drink. Disadvantage: requires a lot pf energy
How is waste water produced?
-When we go to the toilet
-From industrial processes
Harmful chemicals and organic matter must be removed before it is released back into the environment
How can we remove harmful chemicals from waste water?
-Screening/grit removal
-Sedimentation
-Sludge (solid) is treated by anaerobic digestion
-Liquid effluent is treated aerobically
How do we obtain most metals?
From their ores which are mined from the ground.
The pure metal is then obtained by electrolysis or displacement reaction.
What is phytomining?
Plants absorb copper ions into their roots. Burn, then obtain copper from the ash.
What is bioleaching?
Bacteria produce leachate solutions that contain copper ions that can be extracted.
What are disadvantages of phytomining and bioleaching?
Produce very low yields
Why is a life cycle assessment carried out?
To predict the impact of a new product on the environment.
What is considered in a life cycle assessment?
-Extraction & processing of raw materials
-Manufacturing & packaging
-Use over it’s lifetime
-Disposal
-Transportation
How can we reduce our impact?
-Using products less
-Reducing materials & energy needed to make
-Recycling
What is corrosion?
-The destruction of metals over time due to chemical reactions
When do we we say iron rusts?
When it corrodes due to it reacting with oxygen + water
When does copper corrode?
When it reacts with oxygen to make copper oxide
What colour is aluminium oxide?
White
What are sacrificial metals?
Metals that we cover materials with that will corrode before the important metal underneath does
What is galvanising?
Covering another metal in zinc
What are alloys?
Mixtures of metals to fulfil a specific need
What is bronze made up of?
Copper + tin
What is brass made up of?
Copper + zinc
What is jewellery gold made up of?
Gold + silver + copper + zinc
24 carat = 100% gold
18 carat = 75% gold etc
What is steel made up of?
Iron + carbon
What is stainless steel made up of?
Steel + chromium/nickel
Why are alloys stronger than pure metals?
-Different sized atoms disrupting lattice
-Layers cannot slide over each other as easily
What is aluminium used to make?
Light/low density alloys
How is soda-lime glass made?
Heating sand, sodium carbonate + limestone
What is borosilicate glass made from?
Sand + boron trioxide
Has a higher melting point
How is pottery made?
Heating shaped clay in a furnace
What are composites?
A combination of two materials (not two metals), with one binding the other, usually resulting in strong and light materials
e.g. carbon fibre (reinforced polymers)
What causes change in the density of polymers?
The conditions used when making them
What is HDPE?
High density polyethene
What is LDPE?
Low density polyethene
What happens when thermosoftening polymers are heated?
They melt
Why do thermosetting polymers not melt when heated?
Due to crosslinks between polymers increasing the attractive forces between the layers
How does the Haber process work?
-Nitrogen - from air, reacts with hydrogen - from electrolysis of water
-They’re passed over a catalyst at a temperature of 450 degrees celsius and a pressure of over 200 atm (atmospheres)
-The high pressure favours the forward reaction, while a higher temperature increases the rate of reaction but it also favours the reverse reaction so 400 degrees celsius is a compromise temperature
-This is to maximise the yield of ammonia produces, while ensuring the reaction also happens at a reasonable rate
What does the Haber process make?
Ammonia
What elements’ salts are fertilisers made from?
Nitrogen
Phosphorus
Potassium
(NPK fertilisers)
What is ammonia used to make?
Ammonium salts
How are potassium chloride & potassium sulphate obtained?
Through mining
How is phosphate obtained?
Mined phosphate rock
Treated with an acid before being added to the fertiliser
