Appendix 2: Teacher notes - outputs of the lesson

Task 1

Initial weight of each alcohol burner will be slightly different for each student. Table below summarizes data of mass of alcohol burned for different increases of temperature (any increase between 20 to 60 ^oC will provide students with suitable data).

Due to lab safety issues and/or deviations from the procedure that could introduce experimental error, there are some alerts appearing in the application and advising students in various situations (e.g., lighting the wick without water in conical flask, water getting too hot if temperature goes above 85 ^oC, moving alcohol burner with lighted wick, water not being stirred before taking temperature readings and keeping cap off burner without lighted wick for over 1 minute).

Expected range of calorimeter data for combustion of alcohols at different increases of temperature.

Alcohol	ΔT / oC	*Mass alcohol burned / g
methanol
	20	0.71
	40	1.43
	60	2.06
ethanol
	20	0.56
	40	1.12
	60	1.59
propan-2-ol
	20	0.51
	40	0.95
	60	1.42
butan-1-ol
	20	0.43
	40	0.82
	60	1.28

*Average values for five trials

Students should supply data from at least two replicates and present average of theses for their selected increase of temperature.

Task 2

Students will calculate the ΔH combustion value for each alcohol.

Expected set of experiment data for the combustion of alcohols (at ΔT of 20 ^oC).

Alcohol	ΔH combustion/ KJ mol-1
Methanol	380
Ethanol	697
Propan-2-ol	1045
Butan-1-ol	1393

Students should comment on the disparity between their experimental data and the data published in the Handbook of Chemistry and Physics. Ensure students discuss the limitations of the simple experimental set up identifying the major source of errors and suggesting some improvements.

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