L03. Burning hydrocarbons
Lesson Outcomes
How I did
Targets
APP AF1, AF2, AF3, AF4
HSW 1a, 2c
Task 1:
Describe what happens when hydrocarbon
fuels burn, and how the products of
combustion can be identified.
Grade C
Task 2:
Explain:
• the advantages of complete combustion
and link this to the choice of fuels.
• The problems associated with incomplete
combustion
Grade B
Task 3:
Write balanced symbol equations for
complete, and incomplete, combustion
Grade A/A*
Connector: (Grade D)
Answer in full sentences
1. What is a fuel?
2. Name three fuels.
3. What do you consider
to be the most important
properties of a fuel?
4. What is the scientific word
for when a fuel burns?
1. A fuel is a substance that contains stored chemical energy.
When fuels are burned in the air (with oxygen) they release
heat and light energy.
2. petrol, wood, ethanol, coal, macaroni, sugar, etc.
3. A good fuel would release a lot of heat energy with little or no
polluting or harmful by-products.
4. Combustion
BIG picture
• What skills will you be developing this lesson?
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ICT
Numeracy
Literacy
Team work
Self management
Creative thinking
Independent enquiry
Participation
Reflection
• How is this lesson relevant to every day life?
(WRL/CIT)
Task 1 (Grade C)
• Task 1:
Describe what happens when hydrocarbon fuels burn, and how
the products of combustion can be identified.
Keywords for Task 1:
Combustion,
Complete combustion
Fuel
Compounds
containing H and C
are called?
Combustion
fuel
Many fuels like coal, oil, petrol, candle wax,
and natural gas are called HYDROCARBONS
The products of burning a hydrocarbon
to pump
water
water
and
ice
and ice
limewater
anhydrous cobalt
chloride paper
Hydrocarbons are compounds of carbon and hydrogen ONLY.
When pure carbon is burned, carbon dioxide is formed and when
hydrogen is burned, water is produced.
1. What happens to the anhydrous cobalt chloride paper?
2. What happens to the limewater?
3. Explain the significance of the above observations.
Task 1: Review
Go back to your lesson outcome grid and fill out
the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
Task 1:
Describe what happens when
hydrocarbon fuels burn, and
how the products of
combustion can be identified.
Grade C
How I did
Met?
Partly met?
Not met?
Targets
How can I improve
on task 1?
Task 2 (Grade B)
• Task 2:
Explain:
– the advantages of complete
combustion and link this to the
choice of fuels.
– The problems associated with
incomplete combustion
• Task 2: Extension
Keywords for Task 2:
•
•
•
•
•
•
•
•
Combustion,
Complete combustion,
Fuel
Carbon monoxide,
Incomplete combustion,
Pollution,
Soot,
Toxicity
From the
pictures
below,achoose
best fuel.
What
makes
good the
fuel?
Explain your choice.
Yellow flame, soot
Blue flame, no soot
Yellow flame, soot, ash
(residue)
Summary exercise
energy
• Fuels contain stored __________
. When fuels
oxygen
burn they react with __________
in the air and
heat
give out __________
energy. This is called a
combustion reaction. Most fuels contain carbon
__________
hydrogen
and __________
atoms. When the fuel burns
these atoms react with oxygen to make
carbon
water
__________
dioxide and __________
.
carbon combustion energy heat
hydrogen oxygen water
Lots of
oxygen:
Complete and incomplete combustion
Methane
+
Oxygen
Carbon
dioxide
+
Water
Carbon
+
monoxide
Water
This is called Complete combustion
Some
oxygen:
Methane
+
Oxygen
This is called Incomplete combustion
Little
oxygen:
Methane +
Oxygen
Carbon
+
Water
(soot)
This is also called Incomplete combustion
To get complete combustion the fuel must be burned in EXCESS O2.
The hazard of incomplete combustion
Why did the man die?
Less amount of available
oxygen caused the release of
colourless, odourless,
poisonous carbon monoxide.
Incomplete combustion
Carbon monoxide
Edexcel video
Question
Homework
• Homework task:
• Due date:
• Criteria for Grade C:
• Criteria for Grade B
Summary
oxygen
• When a fuel burns with a good supply of __________
to
complete
form carbon dioxide and water it is called __________
combustion. When a fuel burns without a good enough
monoxide
supply of oxygen and forms deadly carbon __________
incomplete combustion.
(and/or soot) and water it is called __________
Incomplete combustion can happen in faulty gas boilers if
intake
their air __________
vent is blocked. Carbon monoxide is a
odourless
colourless , toxic gas. It kills because it
__________
, __________
oxygen
stops your blood from carrying __________
.
colourless complete incomplete intake
monoxide odourless oxygen oxygen
Task 2: Review
Go back to your lesson outcome grid and fill out
the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
Task 2:
Explain:
• the advantages of complete
combustion and link this to
the choice of fuels.
• The problems associated
with incomplete combustion
Grade B
How I did
Met?
Partly met?
Not met?
Targets
How can I improve
on task 2?
Task 3: (Grade A/A*)
• Task 3:
Write balanced symbol equations
for complete, and incomplete,
combustion
• Task 3: Extension
Keywords for Task 3:
• incomplete combustion
• complete combustion
Combustion of methane
1.
2.
Write the word equation for combustion of methane.
Write a balanced symbol equation for the combustion of
methane.
Write the balanced symbol equations for these
reactions:
+
Extension task
• Some camping gas stoves run on propane gas. Propane
molecules have the formula C3H8.
• (a) What new chemicals are produced when you burn
propane?
• (b) Write a word equation for the combustion reaction of
propane.
• (c) Write a balanced formula equation for this reaction.
(Hint: you will need five oxygen molecules for every
propane molecule.)
Task 3: Review
Go back to your lesson outcome grid and fill out
the ‘How I did’ and the ‘Targets’ column.
Lesson Outcomes
Task 3:
Write balanced symbol
equations for complete,
and incomplete,
combustion
Grade A/A*
How I did
Met?
Partly met?
Not met?
Targets
How can I improve
on task 3?
Review of lesson – a selection of past paper questions
Question
Can you explain these key words?
Combustion,
complete combustion,
Fuel
Carbon monoxide,
incomplete combustion,
pollution,
soot,
toxicity
Technicians’ list
Demonstration 1
Eye protection
Two gas jars of oxygen
Deflagrating spoon
Two stoppered boiling tubes of hydrogen
Dry cobalt chloride paper (blue)
Forceps
Splints
Limewater (corrosive)
Charcoal
Demonstration 2
Combustion rig