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Topic: Module 2 Q 12 of the sample mark scheme.

20th February 2017 at 12:31pm

Mike Dabbs

3 posts - View

The question requests the composition of beeswax and the ideal answer includes hydrocarbons, alcohols and fatty acids. The analysis given is quite detailed and includes the number of carbon atoms in the molecules and suggests that some care has been taken with the analysis. An identical set of results is given in Yates  but they also give the percentages of the various constituents. All this indicates a rigorous analysis but there are no peer reviewed references to support this analysis.

I have a few concerns. First, all other references that I have seen state that beeswax consists of long chain aliphatic esters, saturated (or partly) or otherwise. Secondly, even from 'A' level days 'alcohol plus acid gives ester and water' so why do we have free alcohol and free acids in beeswax? I am fully aware that it gets more difficult as molecular weight increases.

Thirdly, I am sitting  module 2 next month. How do I answer questions on beeswax compositions?
And fourthly, should the BBKA be showing model answers unless they can prove that they are correct?

I have been retired for some time now and am not up to speed on the currently available kit but I suspect that GC-MS or possibly HPLC-MS could sort this out on an overnight run. Are there any chemists on the forum that could do this?

Finally, can we get any guidance from the exam markers, whoever they may be, or should the matter be referred to the technical committee/
20th February 2017 at 2:43pm

AdamDarling
-- MODERATOR --
Norfolk

5736 posts - View

Question 12 (a) says " Give the typical components of beeswax". 5 points.

I have googled the composition of beeswax and there are a number of papers one can download which go into far too much detail for just a beekeeper without an A-level in Biology to get to grips with! One paper has the same information as Wikipedia - so is it correct to assume that it is right, I wonder?

When I did Module 2, I remembered the composition table and that was enough to pass, repeating it to myself on the day before and the day of the exam despite not being able to recognise a diol or a fatty acid if it landed in my cornflakes! It's a problem with the exam system with a limited marking resource, that you can pass some aspects by learning parrot fashion without understanding what you have leaned. Hence the need for practical tests like the General and the Advanced Husbandry examinations. Section (b) on the physical properties is something, as a beekeeper, I can relate to; It floats on water, it melts at around 64C etc etc.... To get full marks in an exam question, as I understand it, you need to get 5 answers written down to get the 5 marks in this case. I don't quite understand the comment in the model answer saying thet "The C's are not essential but show a distinction candidate". If you already have 5 answers and you have got 5 marks, how can you get even more marks for a distinction?

To answer your question - 'how do I answer a question on beeswax' - I think that you should answer what you believe to be true and give the reference. What I did was to (blindly) give the answer the examiner wanted to see!
20th February 2017 at 8:45pm

Diane Drinkwater
Manchester & District

41 posts - View

One thing that has been said of late about the exams is that 'there are also half marks' ..
So you might need two points for one mark.
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