Reactivity series and extraction of metals Flashcards
Why do some metals react with water?
They want to fill their outer electron shell and become a positive ion.
What is displacement
When a more reactive metal displaces a less reactive metal from a substance.
Recall the pneumonic fro remembering the order of reactivity
Please Sir Can Me And Collin (the) Zebra Ignite Lucky Helen Cruelly (and) Sneakily Gandalf Please
Using the pneumonic recall the order of reactivity including crabon and hydrogen
Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Lead Hydrogen Copper Silver Gold Platinum
How are metals above Carbon extracted
Thropugh electrolysis
How are metals above Hydrogen but below Carbon extracted
Through reduction (using carbon coke or charcoal)
Why do metals that are below hydrogen not need extraction
Because they occur naturally and do not react with other metals
Define oxidation in the terms of electron
Substance loses electrons and becomes positive
Define oxidation in the terms of oxygen
Substance gains oxygen particles
Define reduction in terms of electrons
Substance gains electrons and becomes negative
Define reduction in the terms of oxygen
Substance loses oxygen particles
Outline the four steps of the extraction of iron
- Coke burns and release CO2
- C02 reduces to CO
- Iron ore is reduced by the CO
- Calcium oxide neutralises siliocon dioxide and forms a substance known as slag
What happens at the cathode during elctrolysis
The cathode is the negative electrode and reduction occurs here
(hydrogen or metals form here)
What happens at the cathode during elctrolysis
The Annode is the positive electrode and oxidation occurs here
(non-metals occur here)
Describe the electrolyssi of Lead Bromide
At the negative electrode (cathode) Pb2+ ions are attracted Pb2+→Pb Pb2+ + 2e- → Pb At the positive electrode (annode) Br- ions are attracted Br- → Br2 2Br- →Br2 + e-
How does electrolysis work
Substances wish to have a full outer shell. By melting the substance youa re allowing the ions to move and therefore conduct a charge. When an ectrical charge is passed through the electrodes the ions move towards the one that will allow them to fill their outer shell. This involves either taking electrodes and sending them to the other substance or giving electrodes. Once full the gaseous substance is no longer bound to the solid and evaporates leaving behind the solid metal.
Name the rule for ionic solutions and electrolysis at the positive elctrode (annode)
If the ion is a halogen (fluorine, chlorine, bromine and iodine) then the halogen is produced
If it is not a halogen then it is oxygen that is produced
Name the rule for ionic solutions and electrolysis at the negative elctrode (cathode)
If the ion is more reactive than hydrogen then hydrogen is produced
If te ion is less reactive than hydrogen the metal is produced
Extraction of aluminium ore (bauxite)
Bauxite (Al2O2 + Fe2O3)
List the five steps of phytomining
- Plants absorb copper from the soil
- Plants are gathered and burnt
- Left with copper oxide
- Copper oxide mixed with sulfuric acid
- Copper sulphate is elctrolysed
Name the benefits of phytomining
- Inexpensive
- Cleansd soil
- Cleans air
Name the negatives of phytomining
- Takes along time
2. Poor quality copper produced
List the four steps of bioleaching
- Bacteria breaks down waste copper
- Bacteria is mixed with chemicals
- Result is copper sulfate
- Copper sulphate undergoes electrolysis
Name the benefits of bioleaching
- Cheap and economical
- Environmentally friendly
- Low emissions
Name teh negatives of bioleaching
- Slow
2. Produces dangerous chemicals
Why is water hard to electrolyse
Because it is a covalent liquid and has poor electrical conductivity
Why is water still possible to elctrolyse
Because it does have some free H+ ions and some OH- ions
How can the electrical conductivity of water be improved
By the addition of acid
What happens at the positive elctrode during the electrolysis of water
4OH- → 2H2O + O2 + 4e-
oxidation
What happens at the negative elctrode during the electrolysis of water
2H+ + 2e- → H2
reduction
Recall the test for identifying aqeous Copper 2+, Iron 2+ and Iron 3+
Copper 2+ turns sodium hydroxide deep blue and cloudy
Iron 2+ turns sodium hydroxide olive green
Iron 3+ turns sodium hydroxide red
