reactivity series. metals and water the romans used lead to make water pipes but didn’t know that...
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Metals and water
The Romans used lead to make water pipes but didn’t know that lead reacts slowly with water and makes it poisonous!
Some metals react vigorously with water, some metals react slowly and some do not react at all.
What is the best type of metal to use for water pipes?
What is the test that a metal hydroxide is produced?
Metals and water – general equation
Potassium and sodium are metals that react vigorously with water even when a small amount of each metal is used.
When a metal reacts with water, the products are a metal hydroxide and hydrogen gas. What is the general equation for the reaction of a metal with water?
metal water metal hydroxide hydrogen
hydrogen+lithium hydroxide
water+lithium
2Li + 2H2O 2LiOH + H2
hydrogen+sodium hydroxide
water+sodium
2Na + 2H2O 2NaOH + H2
hydrogen+potassium hydroxide
water+potassium
2K + 2H2O 2KOH + H2
Metals and water – equations
What are the products when each metal reacts with water?What is the balanced symbol equation for each reaction?
Metals and water – observations
James investigated how reactive some metals are when they react with water and made these observations.
Potassium immediately produces a lilac flame as it skims around the surface making a fizzing noise.
potassium
The sodium melts and skims over the surface producing a stream of small bubbles. Sometimes a yellow-orange flame appeared.
sodium
Bubbles of gas are given off quite quickly. When tested with universal indicator the water is now alkaline.
lithiumMetal Reaction with water
Which of these metals is the most reactive with water?Which of these metals is the least reactive with water?
Copper is used in plumbing and silver and gold in jewellery.
Why are these unreactive metals suitable for such uses?
Metals and water – more observations
James investigated how reactive other metals are with water and made these observations.
No reaction.silver
No reaction.copper
Reacts slowly with cold water but reacts quickly with steam.
magnesium
No reaction.gold
Metal Reaction with water
Metals and water – using unreactive metals
The words “plumber” and “plumbing” come from plumbum (the Latin word for lead) because the ancient Romans used lead for their water pipes.
Lead reacts very slowly with water making it poisonous, so this metal is no longer used in plumbing.
Copper is a much better metal for water pipes because it does not react at all with water – plumbers should be renamed coppers!
Put the following metals in order of reactivity based on their reaction with water, starting with the most reactive:copper, gold, magnesium, lithium, potassium, silver, sodium.
potassium
sodium
lithium
magnesium
copper, silver, gold
Metals and water – order of reactivity
Metals and oxygen – general equation
Most metals will react with oxygen. Some metals react faster than others and some may react very slowly or not at all.
metal oxygen metal oxide
When a metal does react with oxygen, the product is a metal oxide. What is the general equation for the reaction of a metal with oxygen?
Magnesium, for example, burns in oxygen with a bright flame.
The magnesium reacts with oxygen to produce magnesium oxide.
magnesium oxideoxygen+magnesium
2Mg + O2 2MgO
copper oxideoxygen+copper
2Cu + O2 2CuO
iron oxideoxygen+iron
4Fe + 3O2 2Fe2O3
Metals and oxygen – equations
What are the products when each metal reacts with oxygen?What is the balanced symbol equation for each reaction?
Shaida investigated how reactive some metals are when they react with oxygen and made these observations.
Which of these metals is the most reactive with oxygen?
Metals and oxygen – observations
The iron filings glowed red and sparkled leaving a brown-black looking solid.
iron
The copper turnings went through reds and oranges and then slowly got a permanent coating of black.
copper
The ribbon burned with a dazzling white flame giving grey-white smoke and ash.
magnesium
Metal Reaction with oxygen
Which of these metals is the least reactive with oxygen?
magnesium
iron
copper
Metals and oxygen – order of reactivity
Put the following metals in order of reactivity based on their reaction with oxygen, starting with the most reactive:
copper, iron, magnesium.
The first scientists to study chemistry were called alchemists. They were interested in many things including finding ways of changing cheap metals into gold. Some were very good at making metals look gold.
Metals and acid – the acid test
Acid was used to find out if gold objects were made of real or fake gold. Most metals react with strong acids. Gold is such an unreactive metal that it does not react with strong acids.
This became known as “the acid test” because it stopped tricksters making false claims that something was gold.The phrase “the acid test” is used today to mean any process that will reveal fakes.
Metals and acid – general equation
Gold is an unreactive metal that does not react with acid.
When a metal reacts with acid, the products are a metal salt and hydrogen. What is the general equation for the reaction of a metal with acid?
metal acid metal salt hydrogen
How does the type of acid affect the type of salt produced?
Other metals, such as magnesium and zinc, react with acid producing bubbles of gas.
The “squeaky pop” test shows that this gas is hydrogen.
hydrogen+magnesium chloride
hydrochloric acid
+magnesium
Mg + 2HCl MgCl2 + H2
hydrogen+aluminium chloride
hydrochloric acid
+aluminium
2Al + 6HCl 2AlCl3 + 3H2
hydrogen+zinc chloride
hydrochloric acid
+zinc
Zn + 2HCl ZnCl2 + H2
Metals and hydrochloric acid – equations
What is made when each metal reacts with hydrochloric acid?What is the balanced symbol equation for each reaction?
hydrogen+magnesium sulfate
sulfuric acid+magnesium
Mg + H2SO4 MgSO4 + H2
hydrogen+aluminium sulfate
sulfuric acid
+aluminium
2Al + 3H2SO4 Al2(SO4)3 + 3H2
hydrogen+zincsulfate
sulfuric acid
+zinc
Zn + H2SO4 ZnSO4 + H2
Metals and sulfuric acid – equations
What is made when each metal reacts with sulfuric acid?What is the balanced symbol equation for each reaction?
hydrogen+magnesium nitrate
nitric acid+magnesium
Mg + 2HNO3 Mg(NO3)2 + H2
hydrogen+aluminium nitrate
nitric acid+aluminium
2Al + 6HNO3 2Al(NO3)3 + 3H2
hydrogen+zinc nitratenitric acid+zinc
Zn + 2HNO3 Zn(NO3)2 + H2
Metals and nitric acid – equations
What is made when each metal reacts with nitric acid?What is the balanced symbol equation for each reaction?
Metal Reaction with cold acid (HCl)
Reaction with hot acid (HCl)
magnesium Fizzed rapidly -
aluminium - Bubbled quickly
copper No reaction No reaction
iron No reaction Slow bubbling
lead No reaction Occasional bubble
calcium Really fast -
zinc Moderate bubbling
-
Metals and acid – observations
Greg investigated how reactive some metals are with hot and cold acid and made these observations.
Which of these metals is the most reactive with acid?Which of these metals is the least reactive with acid?
calcium
magnesium
aluminium
zinc
iron
lead
copper
Metals and acid – order of reactivity
Put the following metals in order of reactivity based on their reaction with acid, starting with the most reactive:
aluminium, calcium, copper, iron, lead, magnesium, zinc.
with oxygenmagnesium
ironcopper
with waterpotassium
sodiumlithium
magnesiumcoppersilvergold
with acidcalcium
magnesiumaluminium
zincironlead
copper
Comparing orders of reactivity
When the orders of reactivity of metals with water, oxygen and air are compared, there is a pattern of results.
Combining the information from all the reactions of metals with water, oxygen and air gives an overall order of reactivitycalled the reactivity series.
potassiumsodiumcalcium
magnesiumaluminium
zincironlead
coppersilvergold
Pleasesend
Charlie’smonkeys
andzebras
inlead
cagessecurelyguarded!
The reactivity series
The reactivity series is the list of metals placed in order of their reactivity.
One way to remember this order is to learn this silly sentence:
incr
easi
ng
rea
ctiv
ity
Using the reactivity series
incr
easi
ng
rea
ctiv
ity
The reactivity series can be used to make predictions about the reactions of metals.
Predictions can be made about simple reactions of metals with oxygen, water and acids.
Predictions can also be made about more complex reactions where one metal is competing with another.
potassiumsodiumcalcium
magnesiumaluminium
zincironlead
coppersilvergold
Metal React with
Prediction
gold acid
calcium water
sodium oxygen
silver oxygen
zinc oxygen
no reaction
fizzing
burns vigorously
very slow reaction
burns moderately
Simple reactions – predictions
Use the reactivity series to predict if a reaction will take place and how intense the reaction will be.
potassiumsodiumcalcium
magnesiumaluminium
zincironlead
coppersilvergold
If the metal is more reactive than the metal in the compound, it competes with the less reactive metal.
+less reactive
metal compound
more reactive metal
When does displacement happen?
The reactivity series can be used to predict if a metal will react with a metal compound (e.g. chloride, nitrate or sulfate).
+ no reactionmore reactive metal
compound
less reactive metal
If the metal is less reactive than the metal in the compound, it will not compete and so there is no reaction.
The more reactive metal pushes out, or displaces, the less reactive metal from its compound.
+less reactive
metalmore reactive
metal compound
copper+magnesium chloride
copper chloride
+magnesium
no reactionmagnesium chloride
+silver
Displacement reactions – examples
The reactivity series can be used to predict if a metal will react with a metal compound.
Will magnesium react with copper chloride?
Will silver react with magnesium chloride?
Magnesium is a more reactive metal than copper, so magnesium displaces the copper from its compound.
Silver is a less reactive metal than magnesium, so silver does not displace the magnesium from its compound.
Displacement reactions – observation
This photograph shows what happens when magnesium reacts with copper sulfate.
Why does the blue colour of the coppers sulfate solution gradually disappear during this reaction?
before after
Magnesium is a more reactive metal than copper and so the magnesium displaces the copper from the copper sulfate solution. This is why the blue colour disappears.
copper+magnesium sulfate
copper sulfate
+magnesium
magnesium sulfate
zinc sulfate
iron sulfate
copper sulfate
magnesium
zinc
iron
copper
= displacement reaction = no reaction
Displacement of sulfates – predictions
Use the reactivity series to predict if there is a reaction when these metals are added to different metal sulfate solutions.
metal
metal sulfate solution
copper+magnesium sulfate
copper sulfate
+magnesium
Mg + CuSO4 MgSO4 + Cu
zinc+magnesium sulfate
zinc sulfate
+magnesium
Mg + ZnSO4 MgSO4 + Zn
iron+magnesium sulfate
ironsulfate
+magnesium
Mg + FeSO4 MgSO4 + Fe
Displacement of sulfates – magnesium
Does magnesium react with and displace these metal sulfates and if so what products are formed?
no reactionmagnesium sulfate
+zinc
iron+zinc sulfate
ironsulfate
+zinc
Zn + FeSO4 ZnSO4 + Fe
copper+zinc sulfate
copper sulfate
+zinc
Zn + CuSO4 ZnSO4 + Cu
Displacement of sulfates – zinc
Does zinc react with and displace these metal sulfates and if so what products are formed?
no reactionmagnesium sulfate
+iron
no reactionzincsulfate
+iron
copper+ironsulfate
copper sulfate
+iron
Fe + CuSO4 FeSO4 + Cu
Displacement of sulfates – iron
Does iron react with and displace these metal sulfates and if so what products are formed?
no reactionmagnesium sulfate
+copper
no reactionzincsulfate
+copper
no reactioncopper sulfate
+copper
Displacement of sulfates – copper
Does copper react with and displace these metal sulfates and if so what products are formed?
iron+aluminium oxide
The more reactive aluminium wins the oxygen from the less reactive iron. The reaction gets so hot that the iron melts!
This is the Thermit reaction and is used to weld railway lines.
Displacement of oxides
Displacement reactions can also occur between a metal and a metal compound that is a solid.
ironoxide
+aluminium
zincoxide
ironoxide
copper oxide
zinc
iron
copper
Displacement of oxides – predictions
Use the reactivity series to predict if there is a reaction when each mixture of a metal and a metal oxide is heated.
metal
metal oxide
= displacement reaction = no reaction
copper+zinc oxidecopper oxide
+zinc
Zn + CuO ZnO Cu
iron+zinc oxideiron oxide
+zinc
3Zn + 2Fe2O3 3ZnO + 2Fe
Zinc is the more reactive than copper and iron.
Displacement of oxides – zinc
Does zinc react with and displace these metal oxides and if so what products are formed?
no reactionzinc oxide
+iron
copper+iron oxidecopper oxide
+iron
2Fe + 3CuO Fe2O3 + 3Cu
Iron is less reactive than zinc but more reactive than copper.
Displacement of oxides – iron
Does iron react with and displace these metal oxides and if so what products are formed?
no reactionzinc oxide
+copper
no reactioniron oxide
+copper
Copper is less reactive than zinc and iron and will not displace either of these metals.
Displacement of oxides – copper
Does copper react with and displace these metal oxides and if so what products are formed?
oxygencalcium
sodium chloride
calcium
iron chloride
gold
hydrochloric acid
potassium
zinccopper sulfate
magnesiumiron oxide
Reaction?Reactants
Displacement reactions – activity
Use the reactivity series to predict if each mixture will react.
potassiumsodiumcalcium
magnesiumaluminium
zincironlead
coppersilvergold
aluminium+magnesium oxide
aluminium oxide
+magnesium
iron+magnesium chloride
iron chloride
+magnesium
no reactionzinc oxide
+silver
gold+copper nitrate
gold nitrate
+copper
Displacement reactions – activity
Use the reactivity series to predict if each mixture will react and complete the word equation.
displaced metal – The metal that is pushed out of a compound by a more reactive metal.
displacement – A reaction in which a more reactive metal replaces a less reactive metal in a compound.
reactive – A substance that reacts quickly or easily.
reactivity – How quickly or easily a substance will react.
reactivity series – The list of metals placed in order of their reactivity starting with the most reactive.
tarnished – A metal that has become dull after reacting with water and oxygen in the air.
Thermit reaction – The displacement reaction between aluminium and iron oxide that is used to weld railway lines.
unreactive – A substance that reacts very slowly or does not react at all.
Glossary
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