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Combustion of Alcohols

Chemistry Industry Related Resources

Use of Chemical Calculations, Moles and Masses

Topic

Summary

Resources

Specifications

Lesson 1

Combustion of alcohols’

Demonstrate methane bubbles

What is ‘good’ fuel

Combustion of alcohols’ Practical - burning methanol, ethanol, propan-1-ol and butan-1-ol

Calculations including extension

Reflection on the lesson

Teachers Notes

Picture

PowerPoint slide 2

Discussion

PowerPoint slide 3 - 9

Plenary Triangle

PowerPoint slide 10 – 23

Worksheet 1

Worksheet 2

Worksheet 3

AQA Unit 3. 13.4 How much energy is involved in chemical reactions?

EDXEL C1 - E5.20 Demonstrate an understanding of the factors that make a good fuel, including: a how easily it burns c the comparative amount of heat energy it produces (calculations involving conversion to joules are not required)

OCR Gateway C3f: Energy

Describe, using a diagram, a simple calorimetric method for comparing the energy transferred in combustion reactions:

• use of spirit burner or a bottled gas burner

• heating water in a copper calorimeter

• measuring the temperature change

• fair tests.

Interpret and use data from simple calorimetric experiments related to the combustion of fuels to compare which fuel releases the most energy.

Lesson 2

Enthalpies of Combustion

Calculating enthalpy of combustion of methane

Calculate the enthalpy of combustion of the alcohol burned in lesson 1 (Higher Tier)

Self Assessment

Homework

Teachers Notes

Demonstrate or show video of the ‘Whoosh Bottle’.

PowerPoint slide 24 - 36

Worksheet 4

Plenary Triangle

Exampro - Home Work questions and Mark Scheme

AQA Unit 3. 13.4 How much energy is involved in chemical reactions?

EDEXEL C2 - 5.2 Define an exothermic change or reaction as one in which heat

energy is given out, including combustion reactions or explosions

5.4 Describe the breaking of bonds as endothermic and the making

of bonds as exothermic

5.5 Demonstrate an understanding that the overall heat energy

change for a reaction is:

a exothermic if more heat energy is released making bonds in

the products than is required to break bonds in the reactants

b endothermic if less heat energy is released making bonds in

the products than is required to break bonds in the reactants

5.6 Draw and interpret simple graphical representations of energy changes occurring in chemical reactions (no

knowledge of activation energy is required)

Explain why a reaction is exothermic or endothermic using the energy changes that occur during bond breaking and bond making.

Use the formula

energy transferred (in J) = m × c × _T to calculate:

• m = mass of water heated

• _T = temperature change.

Calculate the energy output of a fuel in J/g by recalling and using the formula:

energy per gram = energy released (in J) mass of fuel burnt (in g)

Lesson 3 (Brief version)

Consequences of Combustion of Fossil Fuels

Considering the social, economic and environmental consequences of using fuels.

Research & presentation activity

Homework questions

This lesson promotes more independent learning and may be preferable for more able students.

Teachers Notes

PowerPoint slide 37 – 41

PowerPoint slide 42-43

Worksheet 5

AQA Unit 3 13.4 How much energy is involved in chemical reactions

• To consider the social, economic and environmental consequences of using fuels

EDEXEL C1- 1.9 Demonstrate an understanding of how small changes in the atmosphere occur through:

a volcanic activity

b human activity, including the burning of fossil fuels, farming and deforestation

Alternative Lesson 3

(Extended Version)

This lesson is an alternative to the above. This version looks at the environment in more depth and has a very detailed PowerPoint. This version may be preferable for less able students.

PowerPoint slides 44 - 57

Plenary Triangle

Lesson 1 Combustion of Alcohols – Teachers Notes

Teachers Notes

AQA 2011 Specification:

Unit Chemistry 3

13.4 How much energy is involved in chemical reactions?

Knowing the amount of energy involved in chemical reactions is useful so that resources are used efficiently and economically. It is possible to measure the amount of energy experimentally or to calculate it.

· To compare the energy produced by different fuels or food

· The relative amounts of energy released when substances burn can be measured by simple calorimetry, eg. by heating water in a glass or metal container. This method can be used to compare the amount of energy produced by fuels and foods.

Lesson 1

Starter: Demonstrate methane bubbles burning or show picture.

Main: Discussion – What is a ‘good’ fuel?

View PowerPoint ‘C.A.T.S. Introduction’

Practical: Introduce the Plenary Triangle

View ‘Combustion of alcohols’ Powerpoint, Pupil worksheet.

Conduct practical – burning methanol, ethanol, propan-1-ol and butan-1-ol

Calculations: View ‘Calculations’ on ‘Combustion of alcohols’ PowerPoint to support the calculations – including extension calculations.

Plenary – assess learning through Plenary Triangle – the Learning Objectives listed could be assessed using traffic lights, thumbs or smiley faces.

‘Reflection on the Lesson’ allows pupils to self-assess their learning.

Methane Bubbles

( Delivered in partnership with the Department for Education )

( I can carry out an experiment to compare the energy content of fuels. I can produce my own results table and identified dependent, independent and control variables. I have analysed our results and can state which fuel released the most heat per gram of fuel burnt . I can evaluate the experiment and identify sources of heat loss. I can calculate the energy released by each fuel in 2 minutes. I can evaluate my experiment and suggest improvements. I can calculate the number of moles of fuel burnt in 2 minutes. I can calculate the energy released per mole of fuel burnt. I can calculate the energy released per mole of fuel burnt. Name : Plenary Triangle Equation to calculate the energy released in 2 minutes: Equation to calculate number of moles of fuel burnt in 2 minutes: Equation to calculate the energy released per mole of fuel: Foundation Extension )

Heat of Combustion

Worksheet 1

You are comparing the energy released when fuels burn using the equipment below.

Diagram

( 10 cm ) ( Beaker 10 cm above the spirit burner. ) ( Small beaker with 100cm 3 water ) ( Fuel )

Method

Record the mass of the fuel in the spirit burner.

Record the temperature of the water.

Burn the fuel for 2 minutes.

Record the final temperature.

Record the final mass.

BEFORE you carry out the practical you need to DESIGN YOUR RESULTS TABLE.

Calculations

Calculate the mass loss and the temperature rise.

Now calculate the temperature rise per gram of fuel burnt.

Conclusion

Which fuel releases the most energy per gram of fuel?

Evaluation

Identify the dependent, independent and control variables.

What are the sources of error in your experiment?

Heat of Combustion

Worksheet 2

Extension Calculations

How many moles of fuel were burnt?

Finally calculate the ENERGY RELEASED per mole of fuel burnt.

Conclusion

Which fuel releases the most energy per mole?

( Methanol CH 3 OH )

( Ethanol C 2 H 5 OH )

( Propanol C 3 H 7 OH )

( Butanol C 4 H 9 OH )

Worksheet 3

Reflection on the lesson

Look at your ‘Plenary Triangle’.

Which level or levels have you managed to complete?

List TWO things you have done this lesson that you are most pleased about:

1_______________________________________________________

2_______________________________________________________

Give ONE thing in the lesson you think you could improve upon: (hint - look at the plenary triangle for clues)

________________________________________________________

Lesson 2 Enthalpies of Combustion

AQA 2011 Specification:

Teachers Notes

Unit Chemistry 3

13.4 How much energy is involved in chemical reactions?

Knowing the amount of energy involved in chemical reactions is useful so that resources are used efficiently and economically. It is possible to measure the amount of energy experimentally or to calculate it.

· Interpret simple energy level diagrams in terms of bond breaking and bond formation (including the idea of activation energy…)

· Higher Tier: to calculate the energy transferred in reactions, using simple energy level diagrams or supplied bond energies.

· During a chemical reaction:

· Energy must be supplied to break bonds

· Energy is released when bonds are formed

These changes can be represented on an energy level diagram

· In an exothermic reaction the energy released from forming new bonds is greater than the energy needed to break

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