A suite of GCSE science courses developed in partnership with the University of York

Amendments and supplementary information: Triple Science

All through these supplementary notes, remember that you must carry out your own risk assessment and take suitable precautions.

C7 Chemistry for a sustainable world

Activity AC7.13 'Find the Forgery'
Some schools have found that the presence of nickel does not show up
very well using Dithizone as locating agent and 18:Acetone/ 1:HCl/ 1:water as solvent. We are grateful to Annette Quartly of St Anne's School Southampton for the following suggestion.

An alternative is to change the forgery to one without copper, and get
the blue colour from vanadium4+ ions (which do not appear on the
chromatogram). You could also add some iron2+ (which can be resolved as a yellow cone immediately below the pink zinc2+), thereby incorporating at least a component of a cheaper metal in the forgery.

Mix solutions 0.1M in metal ion, in proportions:
Cu2+ : Ni2+ : Zn2+ : Fe2+ : V4+

A (£) 7:1:2:0:0
B (forgery) 0:0:1:6:3
C (50p) 3:1:0:0:0

Activity AC7.3 'Carboxylic acids and their properties'
The activity sheets needs to be changed in two ways:
1 Delete reference to citric acid. It should just say 'acid' because the idea here is that students try different acids.

Citric acid can be a good acid to use for tests of this kind, but not in this context, where the students might be expected to try to write equations. However, there would be no harm in using citric acid as one of the acids, not least to make the point that naturally-occurring acids behave just like other acids.

2 Label the bottom left test-tube to show 'sodium carbonate'.

Activity AC7.6 'Techniques of synthesis'
All our practical guidance was checked by CLEAPSS. If schools have a heating mantle it would be good to use it, but this is not essential in this instance.

Activity AC7.21 'Greener Alcohol'
The weblink for this activity has changed to: www.greener-industry.org.uk.
Note that this activity is essential: it alone covers OCR Specification section C7.5 (points 12-18), "Making ethanol by three methods".

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To access CLEAPSS leaflet PS67 Practical Activities in the New Science GCSEs
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If you discover any difficulties not mentioned by CLEAPSS, please contact Emma Palmery who will either resolve the issue or forward it to CLEAPSS.