Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Prior Learning:
Know what fractional distillation is & how it separates
Keywords:
Carbon monoxide, unburnt hydrocarbons, particles, sulfur
compounds, sulfur dioxide
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Learning Objectives: Identify and explain
• The combustion products formed from fuels.
• That in a combustion reaction, the amount of oxygen available to react
affects the products produced.
• The pollutants produced when we burn fuels.
I will be successful in this lesson if I can:
• Write word equations for the complete combustion of
hydrocarbons (Lvl C).
• Describe differences between incomplete and complete
combustion (Lvl C).
• List pollutants formed when we burn fuels (Lvl C).
• Complete balanced symbol equations for the complete and
incomplete combustion of simple alkanes (Lvl A).
• Explain how nitrogen oxides, sulfur dioxide and particulates
are produced during the combustion process (Lvl A).
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
1. Hydrocarbons contain
7. Carbon dioxide can be
only hydrogen & carbon
tested with a glowing splint
2. Fuels can only be
8. Oxygen can be tested
hydrocarbons
with limewater
3. A fuel is burned to 9. Water can be tested with
release energy
blue cobalt chloride paper
10. Sulfur dioxide can 4.
beFuel is stored
made by burning
light energy
5.
Combustion
is a
fossil
fuels
reduction reaction
6. When hydrocarbons burn in
plenty of oxygen, carbon
dioxide & water is made
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Combustion is the scientific word for burning and is a
type of chemical reaction.
I know…
I know…
BUT STILL
You should
have learnt
this in Yr 7
Combustion is the reaction when a substance burns and
reacts with oxygen to produce heat and light energy.
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
When a substance burns,
it is said to combust.
Combustion is a rapid
reaction between a
substance and oxygen
that releases heat and
light energy.
A fuel is a substance that reacts with oxygen (combusts) to
release useful energy.
Many fractions obtained from crude oil are used as fuels
because they contain hydrocarbons that burn easily and
release a large amount of useful energy.
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
The natural gas, methane, is often burnt for cooking.
Methane is made up of carbon and hydrogen.
What is the
chemical
equation?
 What gas does methane react with when
it burns?
 What substance will the carbon in methane
change into when it burns in oxygen?
 What substance will the hydrogen in methane
change into when it burns in oxygen?
 What is the word equation for the combustion of methane?
CH4
methane
2O2
oxygen
carbon
CO2
dioxide
2H2O
water
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Combustion demonstration
How can we demonstrate
combustion & the
products of combustion
with the provided
equipment?
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Plenty of air is needed to provide enough oxygen for a
hydrocarbon fuel to burn completely.
The blue flame of a gas hob
or a Bunsen burner is an
example of complete
combustion of a hydrocarbon
(in this case, natural gas).
What are the products of the
complete combustion of a hydrocarbon?
hydrocarbon
+
carbon
oxygen 
dioxide
+
water
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
If there is a shortage of air (oxygen), incomplete combustion of
hydrocarbons takes place.
Instead of producing just carbon
dioxide and water, incomplete
combustion also produces
carbon monoxide and/or carbon
(soot). These form tiny particle in
the air (particulates). It also
releases less energy than
complete combustion.
Carbon monoxide is a poisonous gas because it reduces the
ability of blood to carry oxygen.
Most fuels contain sulfur compounds. When the fuel burns, these
sulfur compounds produce sulfur dioxide.
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
With the yellow bunsen flame
the oxygen flow is restricted &
With
the blue combustion
bunsen flame
incomplete
the
oxygen
flow is in a
excess
occurs.
Therefore,
lower &
complete
combustion
occurs.
temperature
is achieved
&
Therefore,
sootcombustion
is producedis most
efficient under these
conditions, producing high
temperatures & only carbon
dioxide & water
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
1.
What type of chemical is propane?
2. How many carbons in its carbon
chain?
3. What happens when there is
plenty of oxygen?
4. What happens when there is
a shortage of oxygen?
DEMONSTRATION: ‘Burning Propane’ C1a 3.3
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Propane is a hydrocarbon used in camping gas. What is the
equation for its combustion?
propane
C3H8
+
+
carbon
oxygen 
dioxide
5O2

3CO2
+
+
water
4H20
How would the equations change if butane was used?
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Complete these word (symbol) equations
1.
Wax
2. Petrol
3.
4.
CH4
6
CH4
oxygen
Oxygen
2O2
8
8O2
Carbon
dioxide
carbon
dioxide
water
Water
carbon
Carbon
monoxide
CO2
2H2O
CO2
2
CO
12
H2O
3
C
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
In pairs, write a summary sentence about as
many of these words as you can….
You will be asked to read out your sentences
& copy down the correct ones
•Combustion
•Nitrogen oxide
•Sulfur dioxide
•Particulates
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
Learning Objectives: Identify and explain
• The combustion products formed from fuels.
• That in a combustion reaction, the amount of oxygen available to react
affects the products produced.
• The pollutants produced when we burn fuels.
I will be successful in this lesson if I can:
• Write word equations for the complete combustion of
hydrocarbons (Lvl C).
• Describe differences between incomplete and complete
combustion (Lvl C).
• List pollutants formed when we burn fuels (Lvl C).
• Complete balanced symbol equations for the complete and
incomplete combustion of simple alkanes (Lvl A).
• Explain how nitrogen oxides, sulfur dioxide and particulates
are produced during the combustion process (Lvl A).
GCSE Core Chemistry
Exam tip; You MUST be able to write equations for burning hydrocarbons. You should be
able to write balanced symbol equations for the combustion of alkanes, given its formula
GCSE Core Chemistry