Reactivity Series Flashcards
Reactivity Series
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Hydrogen
Copper
Silver
Gold
What are the non-metals in the reactivity series?
Carbon and hydrogen
What is predicted to react?
Anything above hydrogen
Does gold tarnish or oxidise?
No
What gas is formed when reactive metals are added to dilute acids?
Hydrogen
How to test for hydrogen?
Put a lit splint into the gas, hydrogen is very explosive, burning the oxygen, for a squeaky pop
How is the reactivity of metals determined?
Based on their reaction with water or dilute acid
What are the two products of a reaction between a reactive metals and a dilute acid?
Salt + Hydrogen
Where does the name of a salt come from?
The first part comes from the name of the metal
The second part comes from the acid used to make the salt
What does hydrochloric acid make?
A chloride
What does sulfuric acid make?
A sulphate (NOT A SULPHIDE)
What does nitric acid make?
A nitrate (NOT A NITRIDE)
Fair test
A fair test is one in which all other variables which could affect the outcome variable are kept constant so that we can conclude that only the change in the input variable caused the change in the outcome variable.
Test to test the order of reactivity of some metals:
Independent/Input Variable: metal types (Mg, Al, Zn, Fe, Cu)
Dependent/Outcome Variable: volume of gas produced or temperature change, measured with a gas syringe (cm^3) or a thermometer (degrees Celsius) respectively.
Control variables: concentration of acid (affects the rate of reaction so you must use the same acid), volume of acid (affects the temperature change so you must measure the volume), the mass of metal (affects the temperature change so you must measure the mass of the metal)
Risks of testing metal reactivity with dilute acids test
- Broken glass - take care handling glassware, can cut
- Dilute acids are irritant - wear safety glasses, wash off skin immediately if it comes into contact with it
- Obey usual lab rules
Method of the metal reactivity with dilute acid experiment
- Measure 20cm^3 of acid into a boiling tube
- Measure temperature initially
- Add 1 small spatula of metal
- Record final temperature
- Record observations
- Repeat above procedure for different metals
Draw the apparatus for reactivity of metals with dilute acid experiment
N/a
How to improve the practical when repeating?
- repetition
- average
- more concentrated acid
- weigh the metal
- all metals are the same shape or form (eg. powder or blocks) due to surface area
Why does copper not react?
It is too unreactive
Why does aluminium not react?
Aluminium is highly reactive with oxygen in the air, hence it quickly forms a thin, protective oxide layer (Al(2)O(3)) on its surface, preventing a reaction with acid. A reaction would take place if there was no oxide layer.
How to test for hydrogen?
Place a lit splint over the test tube, and wait for a squeaky pop.
Why does hydrogen have a squeaky pop?
A squeaky pop is heard due to the fact that hydrogen burns quickly, reacting with oxygen in the air, producing the squeaky pop.
What is a common observation when metals react with dilute acid?
Effervescence (eg. fizzing or bubbling), metal dissolving, or even colour change
What would happen if solid zinc was added to copper (II) sulphate solution?
Word equation:
zinc (more reactive) + copper sulphate -> copper + zinc sulphate
Chemical equation:
Zn (s) + CuSO(4) (aq) -> Cu (s) + ZnSO(4) (aq)
Displacement
A type of chemical reaction where part of one reactant is replaced with another reactant
How does displacement work?
More reactive displaces less reactive
Metal Displacement reaction method
- Using the diagram below as a guide, place a strip of metal in each of the dimples of a spotting tile.
- Add the named solution to the dimple and record your observations in a table
Will a metal displace itself?
No
What is magnesium sulfate?
A colourless solution
What is magnesium?
A shiny grey solid
What is zinc sulfate?
A colourless solution
What is zinc?
A shiny grey solid
What is copper (II) sulfate?
A blue solution
What is copper?
A shiny red-brown solid
What is iron (II) sulfate?
A green solution
What is iron?
A shiny grey solid
What happens when zinc sulfate and copper are combined?
No reaction, as zinc is more reactive, and will not be displaced by copper
What would happen if magnesium and zinc sulfate are combined?
A reaction would take place, but it would not be visible, as when magnesium displaces zinc, zinc is still a shiny grey solid and magnesium sulfate is also a colourless solution.
What would happen if iron (II) sulfate and magnesium were combined?
The green solution fades to colourless magnesium sulfate
A dark grey solid is formed (iron)
What happens when zinc and copper (II) sulfate are combined?
The green solution becomes a colourless zinc sulfate
A red-brown solid, copper, appears
What is a displacement reaction?
A reaction where a more reactive element replaces a less reactive element in a compound.
What is oxidisation?
Gain of oxygen
What is reduction?
Loss of oxygen
What is redox?
A reaction in which both oxidisation and reduction occur.
Observations of the reaction of aluminium and iron (III) oxide
- very bright light (magnesium burns)
- very vigorous reaction
- filter paper ignites
- a lot of heat released or given out
- exothermic
- molten iron is displaced, melts and falls into water in the beaker
Endothermic reactions
Reactions involving the absorption of heat
Exothermic reactions
Reactions involving the release of heat
What is another name for the aluminium and iron (III) oxide reaction?
Thermite Reaction. It is used in everyday life to weld railway and tram tracks together.
Write a word and balanced symbol equation for the aluminium and iron (III) oxide reaction.
Word equation:
iron (III) oxide + aluminium —> iron + aluminium oxide
Chemical equation:
2Al (s) + Fe(2)O(3) (s) —> 2Fe (l) + Al(2)O(3) (s)
Molten
What is the Thermite reaction an example of?
A displacement reaction, as the less reactive metal, iron, has been pushed out of its compound by the more reactive metal, aluminium.
What would happen if iron was heated with aluminium oxide?
Nothing, as iron is less reactive that aluminium and will not displace it.
A reducing agent
A reducing agent causes another substance to be reduced. In the process it is oxidised.
An oxidising agent
An oxidising agent causes another substance to be oxidised. In the process it is reduced.
In the reaction between magnesium oxide and sodium, what is the oxidising agent?
Magnesium oxide
In the reaction between copper (II) oxide and magnesium, what is the reducing agent?
magnesium
In the reaction between zinc oxide and carbon, what is reduced?
zinc oxide
Word and chemical equation of the reaction between iron (III) oxide and carbon monoxide?
iron (III) oxide + carbon monoxide —> iron + carbon dioxide
can produce CO(2)
Fe(2)O(3) + 3CO —> 2Fe + 3CO(2)
Word and chemical equation of the reaction between copper oxide and hydrogen?
copper oxide + hydrogen —> copper + water
CuO + H(2) —> Cu + H(2)O
What are most metals found as?
Compounds
How can metals below carbon in the reactivity series be extracted?
By being heated with carbon
Electrolysis
The process of splitting by electricity to compounds, in order to achieve the metal, when it is more reactive than carbon, being an alternative solution.
What is diamond?
Carbon
Why is gold shiny?
It is unreactive, hence it does not tarnish, when reacting with oxygen in the air.
What is an ore?
A rock that contains a metal compound, mined from the ground, and usually containing impurities (eg. sand).
What is haematite?
An iron ore, such as jewellery or iron (III) oxide.
What does native mean?
A metal that is found pure (eg. gold or palladium).
Some metals decreasing in reactivity
Li, Ce, Mn, Al, Zn, Cd, Sn, Pb, Cu, Pd
What would be used to extract lithium?
Electrolysis
What would be used to extract zinc?
Carbon
Extracting copper using carbon
- Place half a spatula of copper (II) oxide into a crucible
- Add half a spatula of carbon
- Place the crucible on top of a clay pipe triangle on top of a tripod and place on a heatproof mat
- Heat the crucible using the roaring flame of the Bunsen Burner
- Every 30 seconds use tongs to lift the lid of the crucible and let some air in
- Stop heating after 5 minutes and allow apparatus to cool
- Half fill a 100cm^3 beaker with water
- Use the tongs to tip the contents of the crucible into the water
- Use your spatula to stir the mixture and see what you have made
Copper oxide
Black solid
Carbon
Black solid
End result of copper oxide and carbon
Black powder + some orange/ pink solid
What kind of reaction is rusting?
Slow
What metals most commonly rust?
Iron and steel
What conditions are required for rusting?
Humidity (water) and oxygen
What is dissolved in water?
O(2) is dissolved in water, that fish breathe, while the oxygen in H2O is not.
Humidity
When air has water/moisture
Method for rusting test
- Put four test tubes in a test tube rack and label them A, B, C, and D.
- Put the following materials into each test tube, as shown in the diagram
- Into test tube B, put about 2cm depth of calcium chloride (drying agent). Use a spatula
- In test tube C, place about 1cm depth of oil on to the surface of the boiled water
- Leave for a week and observe any changes
Test tube A
Test tube A has water and air, meaning the iron nail will rust
Test tube B
Due the drying agent, there is air but no water, hence it will not rust. The drying agent absorbs the water or water vapour, and the bung prevents the return of any moisture.
Test Tube C
Boiling drives gases out, meaning there will be no air, but only water. The oil layer is to prevent the O(2) from redissolving in the water. Hence, it will not rust.
Test Tube D
It has water and air, like A, but the nail is loosely wrapped in magnesium, which is more reactive, and due to sacrificial protection, the magnesium rusts, but the iron does not.
What is seen in test tube D?
Bubbles of hydrogen due to magnesium’s reaction with water
What is the name of calcium chloride
Drying agent
Could any metal have been used in Test Tube D instead of magnesium?
Yes, as long as it is more reactive than iron, and does not react too strongly with the water
What are consequences of rust?
Rust corrodes iron until nothing is left, and is flaky, but it does not cause tetanus.
What role does salt (sodium chloride) play in rusting?
It accelerates the rate of rusting. Dilute acid also accelerates it
Physical barrier
The act of putting a substance between the iron and water/air
Examples of physical barriers
- Paint is cheap and easy to apply, used for cars, bikes, bridges, or static objects
- Oil and grease are good flexible coating, useful for tools, machinery or bike chains
- Plastic coating is more expensive, but strong and long-lasting, used in wire netting or fences
- Tin plating is strong and non-poisonous, used for food containers
- Electroplating uses electricity to put a thin coating of an expensive metal onto iron, usually with chromium and nickel (eg. gold-plated jewellery reduces ear infections or itching)
Disadvantages of physical barriers
- maintenance
- scratches or breaking
Sacrificial protection
The protection of iron and steel from rusting due to the coating of a more reactive metal, such as magnesium or zinc, as the more reactive metal corrodes to prevent the less reactive metal from rusting, sacrificing itself to save the other metal.
Example of sacrificial protection
- blocks of magnesium metal attached to oil rigs in the North Sea
- blocks of iron bolted to the hulls of iron ships
- bags of scrap magnesium metal attached to underground oil and gas pipes
Disadvantages of sacrificial protection
- the more reactive metal is used up in time
- high maintenance
- consequence is iron rusting
Galvanising
The coating or dipping of a metal in molten zinc, that acts as a physical barrier from air and water, but resorts to sacrificial protection if scratched.
Examples of galvanising
- girders for bridges and buildings
- some car body panels
- motorway crash barriers
- buckets and roofing nails
What is the difference between corrosion and rusting?
Corrosion is a metal wearing out. Rusting is the corrosion of iron or steel.
Why can railway tracks not be painted?
When the train passes, it will scratch the paint off, or the heat released from the exothermic reaction will melt it (friction).
