Year 7: Chemical changes
Learning Objectives
This is what you should know by the end of this topic.
i.
ii.
Secure
Identify examples
of chemical and
physical changes.
Identify the
difference
between
endothermic and
exothermic
reactions.
iii.
iv.
v.
vi.
Exceeding
Describe how to carry out
tests to identify oxygen,
hydrogen and carbon
dioxide.
Describe what an element is.
Explain the reaction between
iron and sulphur using word
equations.
Describe what a compound
is.
vii.
viii.
ix.
Highest
Describe the conditions in
which iron will rust and
explain the rusting reaction
using a word equation.
Use the rusting reaction to
explain how rusting can be
prevented.
Write word equations to
summarise chemical
reactions.
Key Facts
These are the important facts you will need to know to be successful in this topic. Learn them ready for the
end of topic assessment.
No
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Questions
Answers
When a substance changes in appearance; it is reversible
What is a physical change? Give an example. and nothing new is made. Freezing, melting, evaporating,
condensing, diluting and dissolving are physical changes.
When substances react with each other to produce new
What is a chemical reaction?
substances; it is irreversible.
Change in colour, change in temperature and gas
What are three signs of a chemical reaction?
produced (fizzing).
What happens to temperature in an
It increases.
exothermic reaction?
What happens to temperature in an
It decreases.
endothermic reaction?
What is the test for oxygen?
A glowing splint re-lights.
What is the test for hydrogen?
A lit split burns with a ‘squeaky pop’.
What is the test for carbon dioxide?
Limewater turns cloudy.
What is an element?
A substance that contains only one type of atom.
What is the Periodic table?
A list of elements arranged according to their properties.
Aluminium (Al), Chlorine (Cl), Gold (Au), Hydrogen (H),
Name some common elements and give
Iron (Fe), Magnesium (Mg), Oxygen (O), Phosphorus (P),
their symbols.
Sulphur (S), Zinc (Zn).
Which elements in question 11 are metals? Aluminium, Gold, Iron, Magnesium, Zinc.
Which elements in question 11 are nonChlorine, Hydrogen, Oxygen, Phosphorus, Sulphur.
metals?
A substance that contains at least two different types of
What is a compound?
atom.
Name some common compounds and give
Carbon dioxide (CO2), hydrochloric acid (HCl), iron oxide
their formulae.
(FeO or Fe2O3), iron sulphide (FeS), water (H2O)
What is the chemical name for rust?
Iron oxide.
17
18
19
20
21
22
23
24
25
What two elements react to form rust?
Apart from the elements in question 17,
what is else is needed for rusting to
happen?
How can we prevent rusting?
When oxygen is added in a chemical
reaction, e.g. rusting, what do we call this
type of reaction?
What is a word equation?
What is the word equation for the reaction
between magnesium and oxygen?
What is the word equation for the reaction
between iron and sulphur?
What is the word equation to show how
carbon dioxide is made from its elements?
What is the word equation for rusting?
Iron and oxygen.
Water.
Painting or oiling the iron, coating the iron with plastic,
galvanising the iron with zinc, mixing the iron with
another metal (alloying).
Oxidation.
Something that summarises a chemical reaction.
Magnesium + Oxygen  Magnesium oxide
Iron + Sulphur  Iron sulphide
Carbon + Oxygen  Carbon dioxide
Iron + Oxygen (+ water)  Iron oxide
Revision resources
 KS3 BBC Bitesize Science: look at the learner guides, activities and tests for atoms, elements and
compounds and types of reaction (pages 1-2(top half)). These can be found in the chemistry section
under atoms, elements and the periodic table and chemical reactions and tests respectively.
 Intel Education Resources - STEM: go to KS3 chemistry and look at learning steps 7 and 8.
Notes