L03. Burning hydrocarbons Lesson Outcomes APP AF1, AF2, AF3, AF4 HSW 1a, 2c How I did Targets 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 What is a fuel? Name three fuels. What do you consider to be the most important properties of a fuel? What is the scientific word for when a fuel burns?

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. petrol, wood, ethanol, coal, macaroni, sugar, etc. A good fuel would release a lot of heat energy with little or no polluting or harmful by-products. Combustion

BIG picture What skills will you be developing this lesson? 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 and ice water 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. What happens to the anhydrous cobalt chloride paper? What happens to the limewater? Explain the significance of the above observations. C1b.7.1a

How can I improve on task 1? Task 1: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 1: Describe what happens when hydrocarbon fuels burn, and how the products of combustion can be identified. Grade C Met? Partly met? Not met? How can I improve on task 1?

Task 2 (Grade B) Task 2: Task 2: Extension Keywords for 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

What makes a good fuel? From the pictures below, choose the best fuel. Explain your choice. Yellow flame, soot Blue flame, no soot Yellow flame, soot, ash (residue) 9

carbon combustion energy heat Summary exercise Fuels contain stored __________ . When fuels burn they react with __________ in the air and give out __________ energy. This is called a __________ reaction. Most fuels contain carbon and __________ atoms. When the fuel burns these atoms react with oxygen to make __________ dioxide and __________ . energy oxygen heat combustion hydrogen carbon water carbon combustion energy heat hydrogen oxygen water

Complete and incomplete combustion Lots of oxygen: Methane Oxygen + Carbon dioxide Water + This is called Complete combustion Some oxygen: Carbon monoxide Methane + Oxygen Water + This is called Incomplete combustion Little oxygen: Carbon (soot) Water + Methane Oxygen + 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

colourless complete incomplete intake monoxide odourless oxygen oxygen Summary When a fuel burns with a good supply of __________ to form carbon dioxide and water it is called __________ combustion. When a fuel burns without a good enough supply of oxygen and forms deadly carbon __________ (and/or soot) and water it is called __________ combustion. Incomplete combustion can happen in faulty gas boilers if their air __________ vent is blocked. Carbon monoxide is a __________ , __________ , toxic gas. It kills because it stops your blood from carrying __________ . oxygen complete monoxide incomplete intake odourless colourless oxygen colourless complete incomplete intake monoxide odourless oxygen oxygen

How can I improve on task 2? Task 2: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 2: Explain: the advantages of complete combustion and link this to the choice of fuels. The problems associated with incomplete combustion Grade B Met? Partly met? Not met? 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 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.)

How can I improve on task 3? Task 3: Review Go back to your lesson outcome grid and fill out the ‘How I did’ and the ‘Targets’ column. Lesson Outcomes How I did Targets Task 3: Write balanced symbol equations for complete, and incomplete, combustion Grade A/A* Met? Partly met? Not met? 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