Unit 9E
Reactions of Metals
Learning Outcome
• Describe where to find metals on the
periodic table
• Describe some properties of metals
The periodic table
http://www.youtube.com/watch?v=nsbXp64YPRQ
Metals and Non-metals
Metals and non-metals have very different physical
properties. Because of this the position of metals and
non-metals show a pattern in the Periodic Table:
• Metals are on the left and centre.
• Non-metals are mostly on the right
• In between are metalloids – these are like
metals in some ways and like non-metals in
others.
Properties of metals
Metals are all around us.
We use them every day in a variety of forms.
With the person sitting next to you
create a list of items that you use
every day that are made from metals
Properties and Uses
Metals are used for a variety of reasons
because of their many properties.
Use the activity to sort out the property
of metals with their uses.
Property
Strength
Definition
Able to withstand
great force
Suitability for
use
bicycle frames, car
bodies, bridges
Density
Mass per unit3
Malleability
Able to be shaped
by rolling or
hammering
Low density
aluminium in
airplane bodies
Electrical
conductor
Ability to conduct
an electrical
current
copper wires in
cables
Thermal
Conductor
Ability to conduct
a thermal current
Pots and pans for
cooking
car bodies, horse
shoes
Learning Outcome
• State what gas is given off when a
metal reacts with an acid.
• Describe a test for this gas.
Following the instruction card you have
been given carry out the experiment.
Now discuss the results in your groups.
What happened to the light splint?
What did you notice about the rates of the reactions
when you changed the metal?
Copy and complete
When some metals react with acid a ________ is released
showing that a _________ reaction has taken place.
When tested this gas _________ with a _______.
pop
Burns
chemical
gas
From our experiment the reactivity of the metals
is:
Learning Outcome
• Discover if the same gas is given off
with every acid
• Describe a test for this gas.
• Write a general formula for the
reaction of metals with acids.
What is the gas and is it the same for
every reaction of metal with acid?
When you tested some
metals with hydrochloric acid
a gas was given off.
This gas burned with a ‘POP’
Oxygen in the air
Lighted
spill
Mg + acid
Look at the chemical equation below
magnesium +
Mg
+
hydrochloric  magnesium
acid
chloride
HCl

MgCl2
From the equation above the gas must be
Hydrogen
_____________
Will the same gas be
given off if we change
the acid that we used??
+
+
hydrogen
H2
Carry out the experiment as described on the
Experiment work card.
What did you discover about the gas released?
Draw a labelled diagram to show the experiment you
carried out.
Reaction with Metals - general
• Many metals react with acids to release a salt plus
hydrogen gas.
• The general word equation is:
metal
+
acid

a salt
+ hydrogen
• The salt will depend upon the metal and the acid used.
•Hydrochloric acid gives metal chlorides
•Sulphuric acid gives metal sulphates
•Nitric acid gives metal nitrates
•So, for example
magnesium
+ Hydrochloric  magnesium
acid
chloride
+
hydrogen
Use the general equation and the examples below to
write the word equations for the reactions you
carried out.
metal
+
magnesium +
iron
calcium
Zinc +
acid

a salt
sulphuric
acid

magnesium
sulphate
+ nitric acid 
+
sulphuric 
acid
hydrochloric 
acid
+ hydrogen
+
hydrogen
iron nitrate
+ hydrogen
calcium
sulphate
+ hydrogen
zinc
chloride
+
hydrogen
Learning Outcome
• Describe the products of the reaction
between metal carbonates and acids.
• Write a general formula for the
reaction of metal carbonates with acids.
Carry out the experiment as described on
the experiment work card.
Draw and label a diagram to show what
you did.
Consider the questions below:
1. What happened to the lime water?
2. What is the gas that is released?
3. What happened to the colour of the original
solution?
Copy and complete
The limewater changed from clear and _________
to _________.
This shows the gas produced is _________________.
The solution originally was ___________ and changed
to ___________ showing that a chemical reaction had
occurred.
Metal carbonates and acids
• When metal carbonates react with
acids they fizz giving off carbon
dioxide gas.
• Most metal carbonates are not very
soluble and so reactions may be slow.
The general word equation for these
reactions is:
Metal carbonate + acid  a salt + water + carbon dioxide
• Now write the word equation for the
reaction you carried out.
copper
carbonate
+
sulphuric
acid

calcium
chloride
+
water
+ carbon
dioxide
Metal carbonates and acids
Metal carbonate + acid
 a salt + water + carbon dioxide
zinc
+ sulphuric 
zinc
carbonate
acid
sulphate
ZnCO3
+
H2SO4

ZnSO4
+ water +
+
H2O
+
carbon
dioxide
CO2
sodium + hydrochloric  sodium + water +
carbonate
acid
chloride
carbon
dioxide

CO2
Na2CO3
+
nickel
+
carbonate
NiCO3
+
2HCl
nitric acid
2HNO3


2NaCl
nickel
nitrate
Ni(NO3)2
+
H2O
+
+ water +
+
H2O
+
carbon
dioxide
CO2
Learning Outcome
• Describe the products of the reaction
between metal oxides and acids.
• Write a general formula for the
reaction of metal oxides with acids.
Metal Oxides
What are metal oxides?
Metal oxides are formed when a metal reacts with oxygen
in the air.
Metal oxides and acids
• Most metal oxides are not soluble.
• This means their reaction with acids is
often slower.
• Heating can help to speed up the
reaction.
Carry out the experiment as instructed
Draw and label a diagram into your jotter
Acid
What did you notice?
Oxide
Using the general equation you have been
given can you write the word equation for
the reaction you have just carried out?
Copper
oxide
+
sulphuric
acid

copper
sulphate
+
water
Where is the salt??
From your word equation you have
created copper sulphate salt.
Acid
What could we do to extract the copper
sulphate from the water to check our
equation?
Oxide
Metal oxides and acids
 a salt + water
Metal oxide + acid
zinc oxide
+
sulphuric
acid

zinc
sulphate
+
water
ZnO
+
H2SO4

ZnSO4
+
H2O
sodium
chloride
+
water
2NaCl
+
H2O
sodium
oxide
+ hydrochloric 
acid
Na2O
+
2HCl
iron oxide
+
nitric acid
Fe2O3
+
3HNO3

 iron nitrate +
water

3H2O
Fe(NO3)3
+
Learning Outcome
• Describe what acid rain is and how it is
formed
• Explain some of the problems
associated with acid rain
• Describe some methods to reduce acid
rain.
Your task……….
• Create an informative article for a
newspaper. You must include –
– Pictures
– An explanation of what acid rain is
– An explanation why acid rain is a
problem
– Methods of reducing acid rain
Learning Outcome
• Be able to state what is formed when an
acid reacts with metals, metal
carbonates and metal oxides.
In your teams!!
You must create 3 sets of individual cards
with:
Reactant names
Arrows
Product names
e.g.
Hydrochloric
acid
+
Magnesium
chloride
Magnesium
Hydrogen
+
Once your cards are made:
You will pass your cards to the next
group.
You will be passed cards by another
group.
You now have 10 minutes to
unjumble the cards you have
been given and lay out on the
desk in front of you the
correct answers
Now a runner from the group who
made your cards will come and assess
your answers!!
This will be added to the quiz
scores!!!!
GOOD LUCK!
Learning Outcome
• Be able to explain what neutralisation is
and what the products of neutralisation
are.
Neutralisation
When an acid is added to an alkali or an alkali added to an
acid, neutralisation takes place: the substance changes
pH to become closer to being neutral.
In your group think about examples from everyday
life where neutralising an acid or an alkali might
be useful. Write your ideas onto a show me board.
Alkali Hazards
Alkalis just like acids can be dangerous to use.
Weak alkalis like calcium hydroxide
(lime water) are irritants and can
cause skin to redden and itch and blister.
Strong alkalis like sodium hydroxide
(caustic soda) are corrosive and can
cause skin to redden and itch and blister.
Learning Outcome
• Describe what an ion is.
• Explain how salts are formed from ions.
Bases
Bases are substances that neutralise acids.
Bases are usually:
•Metal hydroxides
•Metal oxides
•Metal carbonates
contain OH
contain O
contain CO3
The following general word equation describes
neutralisations:
acid
+
base

a salt
+
water
In the case of carbonates we also get carbon dioxide.
Alkalis
Bases are substances that neutralise acids.
Alkalis are soluble bases.
Although both can neutralise acids solubility is
important when it comes to the pH of
solutions. For example, adding sodium
hydroxide to water gives a solution with a pH
of about 14.
When calcium carbonate is added to water it
does not dissolve and so the pH remains
close to 7. Even so it can neutralise acid that
is added although more slowly than a soluble
base might.
Neutralisation - Indigestion
If we have too much acid in our stomachs, we
get indigestion.
Acid can move up out of our stomach creating
a burning feeling in the chest.
We neutralise the excess acid by taking a tablet containing
a base.
This is usually a carbonate or an oxide.
Strong soluble bases (like sodium hydroxide) would create
too alkaline a solution and cannot be used.
Acid
1 2 3 4 5 6
7
8 9 10 11 12 13 14
Alkali
Neutralisation - Stings
A bee sting is acidic.
A wasp sting is alkaline.
So one way to treat an acidic bee sting is to
dab on a base: bicarbonate of soda more
properly known as sodium hydrogen
carbonate.
One way to treat a basic wasp’s sting is with
an acid : vinegar - ethanoic acid.
Neutralisation – Soil pH
Plants remove compounds from the soil in a way
that tends to leave the soil acidic.
Many plants won’t grow well in acid soil and so
farmers have to regularly check the pH and
adjust it by adding a base.
Calcium carbonate or calcium
hydroxide are cheap and so are
often used for this purpose.
Neutralisation – Soil fertilisers
Plants also remove nitrogen compounds from the soil and
this is often replaced using fertiliser.
Ammonia is a water soluble gas high in nitrogen and in
some countries it is injected directly into moist soil.
However, because it is a gas much of it is quickly lost.
In the UK ammonia is dissolved in water to give
ammonium hydroxide (an alkali) and this is neutralised
by reacting it with nitric acid to give a solid nitrogen rich
fertiliser.
ammonium
hydroxide
NH4OH
+
nitric acid
+
HNO3
 ammonium
nitrate

NH4NO3
+
water
+
H2O
Neutralisation - acid gases
Many power stations burn coal containing sulphur.
When this burns it produces acidic sulphur oxides which
can cause acid rain.
The gases are “scrubbed”, as much as possible,
of these acidic oxides by reacting them with a
base before releasing them into the air.
Calcium oxide or calcium hydroxide are often
used for this purpose.
Acid rain – living things
Steps have been taken to reduce emissions of acidic
sulfur oxides from power stations and nitrogen oxides
from cars.
Even so the atmosphere still contains enough of them to
make the rain from industrial areas quite acidic.
Trees and lakes are badly
affected in many parts of the
world including Northern
Germany and Scandinavia
which suffers from South-West
winds from the UK.
Acid rain damaged tress
Acid rain – metals and stone
Acid rain increases the rate of corrosion of metals.
It also greatly accelerates the rate of chemical weathering
of certain stones used in building such as limestone and
marble. (These stones are carbonates. What gas will be
given off as they dissolve?)
CO2
The metal above the
wheel arch of this car
is rusting away
Learning Outcome
•
•
•
•
Understand the hazards of alkalis
State what a base is
State what an alkali is
Explain the importance of the solubility
of a base in neutralisation
Copy and complete
Bases are substances that _________ acids. When a
base is soluble in water it is called an ___________.
An insoluble base will not alter the pH of ________
but will still neutralise an acid although more ________.
Alkalis are important in a number of situations
e.g. neutralising acidic soil.
Learning Outcome
• Describe 2 ways to find the exact
volume of 1 substance that will
neutralise another substance
A simple way of neutralising a solution is to add an acid to
Am alkali until the indicator turns green.
Using a dropping pipette makes it very difficult to measure
the exact volume of alkali or acid required for the
reaction.
Chemists use burettes
to add small amounts
gradually and to measure
volume added accurately.
Finding the volume
Experiment 1
• Fill the burette with HCl
• Accurately measure 25cm3
. of NaOH (using a pipette)
into a conical flask
• Add 2 drops of universal
indicator
• Now carefully add HCl from
the burette into the conical
flask as shown.
• Record the volume of HCl
needed to neutralise the
NaOH.
Experiment 2
• Accurately measure 25cm3
of HCl into a beaker
• Collect a pH probe and data
logger and insert the pH
probe into the HCl
• Now measure 1cm3 of NaOH
and add it into the HCl.
• Stir and record the pH
• Add another 1 cm3 of NaOH
and repeat.
• Keep adding until the pH on
the data logger reads 7.
Graph the results
Create a graph of pH of solution against
the volume of NaOH added.
Using your graph find the exact volume
needed to neutralise the HCl.
Homework
Write a short essay (300 words) on salts and their
commercial and industrial importance in society.
Learning Outcome
• Describe 2 ways to find the exact
volume of 1 substance that will
neutralise another substance
Learning Outcome
• Describe 2 ways to find the exact
volume of 1 substance that will
neutralise another substance
Learning Outcome
• Describe 2 ways to find the exact
volume of 1 substance that will
neutralise another substance