BTEC Level 3
Subsidiary Diploma
in Applied Science
UNIT4: Scientific Practical Techniques
Assignment 4.1- Identifying Unknown
substances and concentrations
(P1, M1,D1)
Scenario
A number of substances in the laboratory you work in have
been mislabelled. You must conduct a number of tests to
identify some unknown substances and the concentrations of
some known substances. (You should identify hazards and
necessary control measures to reduce any risks.)
What Do I Need To Do?
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carry out quantitative and qualitative analytical techniques (P1)
explain how accuracy may be ensured in the techniques used (M1)
evaluate the quantitative and qualitative analytical techniques used, suggesting
improvements for future investigations (D1)
How Do I Do It?
Produce a report which details the practical work you have completed and provide a full risk
assessment for your investigation.
What Do I Need To Include (Content)?
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A number of unlabelled jars containing different ions need to be tested. Conduct
flame tests and test tube tests for ions to identify the unknown substances. Record
your results clearly along with the test used to identify the contents. (P1)
A cupboard in the laboratory contained a number of substances and pieces of
equipment you believe to be those used to test food stuffs for protein, starch and
reducing sugars. Carry out tests to identify proteins, starch and reducing sugars and
record the results to be sure that the cupboard did indeed contain the substances
and equipment you suspected. (P1)
Write a report explaining how you can be confident that the substances and
concentrations you have identified are true and accurate. Discuss how you ensure
accuracy and prevent any errors in each of the procedures you carried out.
o You could use the following headings to help you to structure your report:
o Accuracy of titrating NaOH wit acid
o Confidence in results: Cations
o Confidence in results: Anions
o Confidence in results: Starch
o Confidence in results: Protein
o Confidence in results: Reducing Sugars (M1)
Find an unknown concentration of acid. (P1)
Write well-structured and detailed report which includes a summary of sources of
error, as well as, suggestions for how to improve the methods used, or suggesting
alternative methods. Safety information will help you achieve (D1).
Due Date 04/03/2014