Combusiton of alcohols

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Heat energy from alcohols

This experiment compares the amounts of heat energy produced by burning various alcohols.

Read our standard health & safety guidance
Lesson organisation

Thisexperiment is suitable for pre-16 students, possibly as an introduction to a topic on fuels. It can be taken further if used with post-16 students who can calculate values for enthalpy changes ofcombustion, with subsequent discussion about heat losses and incomplete combustion.

The alcohols should be provided in labelled spirit burners ready to use. If each group investigates one alcohol, theexperiment can be done in around 20 mins. It is better if each spirit burner is used by more than one group of students. Variation of results will add substance to a discussion about errors.
Apparatus andchemicals

Eye protection

Each group of students requires:

Retort stand and clamp
Conical flask (150 cm3 or larger)
Measuring cylinder (100 cm3)
Thermometer (-10 °C to +110 °C)
Access tobalances, preferably several, to avoid queuing.

Groups require access to spirit burners (see note 1), with wicks and caps, containing the following highly flammable alcohols, which are alsovolatile and have low flash points.

Methanol (Highly Flammable, Toxic)
Ethanol (Highly Flammable)
Propan-1-ol (Highly Flammable, Irritant)
Propan-2-ol (Highly Flammable, Irritant)
Butan-1-ol(Flammable, Irritant, Harmful)
Technical notes

Methanol (Highly Flammable, Toxic) Refer to CLEAPSS Hazcard 40B
Ethanol (Highly Flammable) Refer to CLEAPSS Hazcard 40A
Propan-1-ol (Highly Flammable,Irritant, Harmful) Refer to CLEAPSS Hazcard 84A
Propan-2-ol (Highly Flammable, Irritant, Harmful) Refer to CLEAPSS Hazcard 84A
Butan-1-ol (Harmful) Refer to CLEAPSS Hazcard 84B

1 Suitable spiritburners are hard to come by. Ideally they should be small, with a capacity of 50 cm3 or less. Pictures and information in suppliers' catalogues can be misleading. If capacity is more than 50 cm3, reduce...
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