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KS3 Chemistry

9F Patterns of Reactivity



Metals and acid

Summary activities

Reactivity series and displacement

Metals and water

Metals and oxygen

Contents


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 acid

Summary activities


Metals and water

Metals and oxygen

Contents


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 oxide�oxygen+magnesium

2Mg + O2 � 2MgO

copper oxide�oxygen+copper

2Cu + O2 � 2CuO

iron oxide�oxygen+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.

magnesiumMetal 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.



Metals and acid

Summary activities


Metals and water

Metals and oxygen

Contents


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 – experiment


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 hydrogenHow 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


+aluminium

2Al + 6HCl � 2AlCl3 + 3H2

hydrogen+zinc chloride


+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 nitrate�nitric 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?


calciummagnesiumaluminium

zincironlead

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.


Metals and acid – reactivity activity



Metals and acid

Summary activities


Metals and water

Metals and oxygen

Contents


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 re

activ

ity


What is the order of metals?


Using the reactivity series

incr

easi

ng re

activ

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.


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.


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 reaction�more 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 metal

more reactive metal

compound


copper+magnesium chloride

�copper chloride

+magnesium

no reaction�magnesium 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 reaction�magnesium 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?

✓

✓

✗



+iron

no reaction�zincsulfate

+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?

✓

✗

✗



+copper

no reaction�zincsulfate

+copper

no reaction�copper 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 oxide�copper oxide

+zinc

Zn + CuO � ZnO Cu

iron+zinc oxide�iron 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 reaction�zinc oxide

+iron

copper+iron oxide�copper 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?



+copper

no reaction�iron 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.


magnesiumaluminium

zincironlead

coppersilvergold

✓

✗✓✓✗

✓


aluminium+magnesium oxide

�aluminium oxide

+magnesium

iron+magnesium chloride

�iron chloride

+magnesium


+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.



Metals and acid

Summary activities


Metals and water

Metals and oxygen

Contents


�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


Anagrams


True or false?


Multiple-choice quiz

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