C6 - Global challenges Flashcards
What are ores?
Naturally occurring rocks which contain metal compounds
What is the name of the aluminum ore and what is it made of?
Bauxite (aluminum oxide)
What is the name of the iron ore and what is it made of?
Haematite (Iron oxide)
What is the name of the copper ore and what is it made of?
Malachite (Copper Carbonate)
What does Extraction mean?
Obtaining pure metal from ore
Reactivity series for metal extraction?
Please Send Lions Cats Monkeys And Cute Zebras Into Lovely Countries Signed General Penguin
Potassium Sodium Lithium Calcium Magnesium Aluminum Carbon Zinc Iron Lead Copper Silver Gold Platinum
What is group 1 of reactivity series and how are the metals extracted?
Potassium Sodium Lithium Calcium Magnesium Aluminum
Extracted by electrolysis (using electricity)
What is group 2 of reactivity series and how are the metals extracted?
Zinc
Iron
Lead
Copper
Extracted by reduction using Carbon
What is group 3 of reactivity series and how are the metals extracted?
Silver
Gold
Platinum
No extracted needed as they are found as pure metals
Why can’t the reduction using carbon method work on the group 1 of the reactivity series?
They are more reactive than carbon, therefore carbon cannot remove the oxygen.
Why do most metals exist as compounds in Earth’s crust and some exist as native metals?
Most metals exist as compounds as they are too reactive to exist on their own.
Some metals (like silver, gold, platinum ) are native metals (pure metals) as they are too unreactive to form compounds.
Example of reduction using carbon with iron oxide?
Iron oxide + carbon -> Iron + Carbon dioxide
Why is aluminum oxide melted when extracting aluminium?
When solid it cannot conduct electricity (in electrolysis) as ions are not mobile and in liquid the ions are mobile and can conduct electricity
Why is Cryolite used in extraction of aluminum oxide?
It lowers the melting point of aluminum oxide - which has a very high melting point
Equipment for extraction of aluminum from aluminum oxide?
- Graphite (Carbon) anodes in a solution of molten bauxite and Cryolite
- Solution in a steel container with the inside of the container being the cathode
Word and symbol equation of the extraction of aluminum from bauxite.
Aluminum oxide -> Aluminum + Oxygen gas
2Al2O3 -> 4Al + 3O2
What attracts and happens at the cathode in the extraction of aluminum from bauxite?
Aluminum ions (+) attract to the cathode (-) and reduction occurs to from aluminum atoms:
Al(3+) + 3e- -> Al
What attracts and happens at the anode in the extraction of aluminum from bauxite?
Oxygen ions (-) attract to the anode (+) and oxidation occurs to from Oxygen atoms:
2O(2-) - 4e- -> O2
Why does the anode become smaller as the extraction of aluminum takes place?
The oxygen gas produced at the anode reacts with the Carbon anodes to produce Carbon dioxide.
Some uses of alumnium?
Bicycles: as aluminum is light and doesn’t rust
Aeroplanes: Low density (light)
What is phytomining definition?
Extracting copper from low grade ores by hyperaccumulator plants.
What is bioleaching definition?
Extracting copper from low grade ores by microorganisms like bacteria
What is a hyperaccumulator plant?
A plant that can absorb toxic metals without dying used in phytomining
How do we extract copper via phytomining?
1) Grow hyperaccumulator plants over low grade copper ore
2) Roots of plant absorb copper ions from soil via active transport
3) Once copper ions are in leaves, harvest and burn the plant to produce ash
4) The ash is rich in copper compounds - copper has reacted with oxygen in combustion to form copper oxide.
5) Use displacement method or electrolysis to extract pure copper
How do we extract copper via bioleaching?
1) Bacteria feeds on the low grade copper ore
2) A solution is produced (called a leachate) containing copper compound (Like copper sulphate)
3) Iron can be used to displace copper from the copper compound
IRON + COPPER SULPHATE -> IRON SULPHATE + COPPER
Advantages and disadvantages of:
- Phytomining
- Bioleaching
PHYTOMINING
Adv: Conserves supply of more valuable copper ores from being used up
Dis: Slow
BIOLEACHING:
Adv: Doesn’t require high temperature like traditional mining
Dis: Can produce toxic substances like sulphuric acid
Slow
What is the Haber process?
- Word and symbol equation
Creating Ammonia from Nitrogen and Hydrogen
Hydrogen + Nitrogen ⇌ Ammonia
3H2 + N2 ⇌ 2NH3
Where do we get the reactants for the Haber process?
And disadvantage of it
NITROGEN: The air from cryogenic distillation - distillation by cooling the air instead of heating
or extracted from air
DISADVANTAGE:
- Requires lots of energy
- Needs to be done multiple times to make sure no oxygen contaminates the Nitrogen gas as it can damage the Iron Catalyst
HYDROGEN: From petroleum after distillation of crude oil by reacting methane with steam. Sulfur has to be removed as an impurity damages the catalyst
or taken from naturally occurring gas
DISADVANTAGE:
-More energy required so more cost
What are some uses for ammonia?
- Fertilisers
- Nitric acid
- cleaning fluids
Conditions for Haber Process?
- High pressure of 200 atm increases ammonia yield as it shifts equilibrium to the right
- High temperature decreases percentage yield but increases rate of reaction
- A compromise 450 degrees Celsius - optimum temp to give a fast reaction and high percentage yield
- Catalyst of Iron increasing rate of reaction but not percentage yield
Haber process: What does High temperature do? What does low temperature do? What does High pressure do? What does Low pressure do? What does adding a catalyst do?
N2 + 3H2 -> 2NH3
(Forward = Exothermic)
High temp: Lower yield of ammonia
Low temp: High yield of ammonia
High pressure: High yield, equilibrium shifted to the right
Low pressure: Low yield, equilibrium shifted to the left
Catalyst: Nothing to the yield, Increased rate of reaction
Factors that increase or decrease the cost of the Haber process?
Increased cost:
- High temperature
- High pressure
- Machinery / Automation
Lower cost:
- Catalyst
- Recycling material
What is the contact process?
Producing Sulphuric acid or oleum from the raw materials water, Sulphur and oxygen
Step to contact process (including word and symbol equations):
1) Sulphur burnt in Oxygen to produce Sulphur dioxide
Sulphur + Oxygen -> Sulphur dioxide
S(l) + O2(g) → SO2(g)
2) Sulphur dioxide reacted with Oxygen to produce Sulphur trioxide
Sulphur dioxide + Oxygen ⇌ Sulphur trioxide
2SO2(g) + O2(g) ⇌ 2SO3(g)
3) Sulphur trioxide dissolved in water to produce Oleum
Sulphur trioxide + water -> Oleum
2SO3 + H2O → H2S2O7
4) Sulphur trioxide reacts with water to form sulphuric acid
Sulphur trioxide + water -> Sulphuric acid
SO3 + H2O → H2SO4
Conditions for Contact process:
- 1 or 2 atmospheric pressure
- Around 450 degrees
- Catalyst Vanadium Oxide (V2O5)
Contact process: What does High temperature do? What does low temperature do? What does High pressure do? What does Low pressure do? What does adding a catalyst do?
High temperature: Lower yield as equilibrium shifts left and increases rate of reaction
Low temperature: Higher yield as equilibrium shifts right and slower rate of reaction
High pressure: Decreases yield but faster rate of reaction
Low pressure: Increases yield, and decreases rate
Vanadium oxide catalyst: Nothing occurs to yield but rate of reaction increases
Plants and solid fertilisers:
Plant roots cannot absorb solid fertilizers but they can absorb dissolved fertilizers (in liquid form)
What are the 3 essential elements in fertilisers?
Nitrogen (N)
Phosphorous (P)
Potassium (K)
What does minerals do in plants?
Nitrates: used to make amino acids for proteins needed for cell growth
Phosphates: Used to make DNA and cell membranes for respiration and growth
Potassium: helps enzymes for respiration and photosynthesis
Magnesium: makes chlorophyll for photosynthesis
Plant minerals and plant deficiencies?
Lack of nitrates
-Poor growth / yellow leaves
Lack of Phosphates
-Poor root growth and purple leaves
Lack of Potassium: Poor flower + fruit growth and spotted leaves
Lack of magnesium: yellow leaves
How are fertilizers chemically formed?
Formed by a base + acid by titration
EG
Ammonium sulphate - made from ammonia hydroxide (alkali) and sulphuric acid
Ammonium nitrate - made from ammonia hydroxide and nitric acid
Method for creating a fertilizers?
1) Fill burette with acid and measure starting volume
2) Use pipette to measure specific amount of ammonium (ammonia hydroxide) and transfer it to a flask
3) Add pH indicator
4) Slowly begin adding acid until there is colour change - the alkali has been neutralized - and measure the amount of acid needed to neutalise alkali
5) Repeat steps until there is a consistent result
6) Fertiliser is contaminated with pH indicator causing it to be coloured so titration needs to be done again without indictor adding volume of acid required to neutalise alkali gathered from previous
7) Neutralised solution needs to be evaporate is rid of water from it because water is also a product (EG: ammonia hydroxide + sulphuric acid -> ammonia sulphate + water)
8) Evaporate solution, to form crystal and filter off crystals to leave Fertiliser
What is the LCA (Life cycle assessment)?
- a way of analyzing the ‘life’ of a product and see how much water and energy is used and the effects in the environment
General steps to the LCA?
1) Raw materials (eg biodegradable, where it came from, transportation)
2) Manufacture (toxic chemicals produced, energy/water required etc.)
3) Transportation
4) Uses (reusable, last long)
5) Disposing (recyclable, landfill vs incinerators)
Definitions for LCA topic:
Biodegradable Objectivity Subjectivity Quantitative Qualitative
Biodegradable: Can be decomposed by bacteria
Objectivity: fact
Subjectivity: opinion
Quantitative: numbers
Qualitative: descriptive (words)
4 materials that can be recycled?`
- Paper
- Plastic
- Glass
- Metals
Reduce, Reuse, Recycle definitions and one advantage?
Reduce - stop using as much materials in the first place (like walking instead of driving)
ADV - Reduces environmental impacts and waste
Reuse - Reusing items instead of disposing or recycling them
ADV - Reduces rubbish in landfills and incinerators
Recycling - Crushing, melting materials into a new product
ADV - Reduces need for quarreling natural resources
What is an alloy?
A mixture of two or more metals to change the metals properties
Why are alloys more stronger than pure metals?
Pure metals consist of ions in a lattice therefore when hit the layers can slide over each other making them soft.
However, in alloys the different sized particles disrupt the lattice arrangement making it harder for layers to slide over each other - they are stronger
What is the alloy bronze made of and its uses?
Copper and tin
-Used for statues
What is the alloy brass made of and its uses?
Copper and zinc
-used for musical instruments and water taps
What is the alloy Steel made of?
Carbon and Iron
The higher the carbon percentage the stronger the alloy but it is more brittle (break easier)
What is the alloy stainless steel made of and its uses?
Nickel and Chromium
- Doesn’t rust
What is the alloy Solder made of?
Lead and tin
What is the alloy Amalgam made of?
Any alloy containing mercury
Why is gold alloys used in jewellery instead of the metal itself?
The metal gold is too soft therefore alloys containing gold are used measured in carats.
What equation do you use to find the percentage of a metal present in its alloy?
Percentage of metal in alloy = (Mass of metal / Total alloy mass) x 100
What is the difference between Rusting and Corrosion?
Rusting - occurs only with Iron
Corrosion - occurs with any other metal
Conditions for Rusting?
- Oxygen
- Water
- Salt (Not required but catalysis rusting process)
Word and symbol equation for rusting?
Iron + water + oxygen -> Hydrated Iron (III) oxide
4Fe + 3O2 + 2H2O -> 2Fe2O3.H20
How to prevent rusting?
- Removing the reactants from the rusting equation: water or oxygen
- Cover with physical material - like oiling or painting so iron isn’t exposed to air
- Sacrificial protection
- Galvanising
Sacrificial protection vs Galvanising vs tinning:
Sacrificial protection: Iron coated in a more reactive metal
- EG Magnesium is way more reactive than iron so it reacts with air and ‘sacrifices’ itself protecting the iron
An example of sacrificial protection is Galvanising:
Galvanising: Iron coated in zinc
- Zinc is more reactive than iron so it will react with the air instead of it
Tinning: Iron coated in tin
-Tin is less reactive and doesn’t reactive with oxygen so tin inside is protected
Rusting in:
1) Boiled water
2) Salt water
3) Water
4) Air
5) Air + Calcium Chloride
1) Boiled water = no rusting as boiled water has no oxygen in it
2) Salt water = lots of rusting as salt speeds up rusting
3) Water = Rusting as water contains oxygen
4) Air = Rusting as air contains moisture
5) Air + Calcium Chloride = no rusting as calcium chloride dries air removing the water
Definitions for properties:
- Tensile strength
- Compressive strength
- Hardness
- Brittle
Tensile strength: Ability to withstand stretching without breaking
Compressive strength: Ability to withstand compression (squashing) without breaking
Hardness: Ability to resist wear, stretching or indentation
Brittle: A material that can be easily broken
What are ceramics?
A hard non- metallic material made from metals and non metals - they form giant ionic lattices or giant covalent structures
Properties of ceramics?
- High melting points
- Hard and stiff, but brittle
- Poor thermal and electrical conductors
- Chemically unreactive as they contain mostly oxides
How are glass ceramics made?
Made by melting sand (silicon dioxide) which is allowed to cool into solid
How is clay ceramics made and some examples of clay ceramics?
-Brick, china, porcelain
Made by heating clay at high temperatures which cause crystals to form and join together.
They are often coated in a glaze which hardens on heating to form a hard, smooth, opaque waterproof layer.
What are composite materials and some examples of them?
-Concrete, wood and fiberglass
Made of 2 components:
1) The reinforcement - materials that make up the bulk of the comospite
2) The matrix - substance binding the composite together
How is soda-lime glass made and what are its properties?
Made by heating a mixture of sand, sodium carbonate and limestone
PROPERTIES:
- Transparent
- Doesn’t conduct electricity
How is borosilicate glass made and what are its properties?
Made from sand and boron trioxide
PROPERTIES:
-Melts at higher temperature than soda-lime glass
Properties of composites?
- light weight
- Insulator
Thermosetting polymers vs Thermosoftening polymers
THERMOSOFTENING: consist of individual, tangled polymer chains and melt when heated and can be remolded: the polymer chains can move freely over each other when heated
THERMOSETTING: consist of polymer chains with cross-links between them so they don’t melt when heated - they are hard and brittle
