Open Ended Questions

CfE Higher Chemistry – The dreaded (soon to be loved) open-ended questions

How to deal with them….

You must begin to tackle these questions head on – 6 marks can make a significant difference to a final grade. There is a skill in answering these questions, a skill which needs practice to perfect!

  1. In Higher Chemistry examinations open-ended questions will always be identified by the wording ‘Using your knowledge of chemistry, comment on…’.

  2. Read the question carefully. Pay attention to diagrams, structural formulae or equations that have been included to help you answer the question.

  3. Try to identify which key areas the question relates to from the CfE Higher course, no credit will be given for Nat 5 knowledge.

  4. There will not be a single ‘correct’ answer. Markers will reward your understanding of chemistry.

  5. 3 marks for good understanding (not perfect, just good),
    2 marks for reasonable understanding
    1 mark for limited (if you write any correct chemistry from Higher course should be awarded 1 mark)

  6. Good understanding is demonstrated by EXPLAINING, don’t just state a fact, explain the theory behind it. E.g. If you talk about H Bonding, explain how, why it arises, draw a diagram that represents H – Bonding, you are showing the examiner you have a good knowledge of this aspect of chemistry.

  7. Show your understanding of chemistry by drawing structural formulae, identifying functional groups, writing chemical equations or working out formulae.

  8. You may choose to present your answer as a paragraph, a set of bullet points or even as a diagram.

If you have time at the end of the examination, check to see if what you have written answers the question asked

Week 1 - Click to view answer

Aspirin is a widely used medicine. It is advised that it is stored in dry, cool conditions.

Using your knowledge of chemistry, comment on the reasons why aspirin should be stored under these conditions.

When presented with a molecule it is good to identify the functional groups present and the properties which they have.

Dry

  • As polar groups present like dissolves like

  • H – bonding (explain and give definition)

  • If any moisture present the aspirin will dissolve, don’t want this to happen until it is consumed.

Cool

  • Activation energy

  • Decay /oxidation of molecule – explanations would be important here.

Week 2

Oxygen gas speeds up the rate at which food is spoiled. To improve the shelf-life of foods, food manufacturers use several methods to remove oxygen from inside the food packaging. In one method, an enzyme is added which catalyses a reaction between oxygen and glucose often present in foods.

glucose + oxygen + water → gluconic acid + hydrogen peroxide

Using your knowledge of Chemistry, comment on why this method may not be suitable to improve the shelf-life of all foods.

Week 3

A student makes the following statement:

‘Sugar can be used to produce alcohol, a carboxylic acid and the ester ethyl ethanoate’

Using your knowledge of chemistry, comment on the accuracy of the student’s statement

Week 4

Hydrogen peroxide is used in gels to whiten teeth. The ion–electron equation for the oxidation of hydrogen peroxide is:

H2O2 → O2 + 2H+ + 2e−

Using your knowledge of chemistry, comment on possible methods for measuring and comparing the concentration of hydrogen peroxide present in two different gels. (3)

Week 5

The Periodic Table groups together elements with similar properties. In most Periodic Tables hydrogen is placed at the top of Group 1, but in some it is placed at the top of Group 7.

Using your knowledge of chemistry, comment on the reasons for hydrogen being placed above either Group 1 or Group 7.

Note same question for both year groups – but if answering from HIGHER must contain HIGHER knowledge (not Nat 5)