In Nat 5 Chemistry examinations open-ended questions will always be identified by the wording ‘Using your knowledge of chemistry, comment on…’.
Read the question carefully. Pay attention to diagrams, structural formulae or equations that have been included to help you answer the question.
Try to identify which key areas the question relates to from the Nat 5 course, no credit will be given for Nat 4 knowledge.
There will not be a single ‘correct’ answer. Markers will reward your understanding of chemistry.
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)
Good understanding is demonstrated by EXPLAINING, don’t just state a fact, explain the theory behind it. E.g. If you talk about Ionic Bonding, explain how, why it arises, draw a diagram that represents an ionic bond, you are showing the examiner you have a good knowledge of this aspect of chemistry.
Show your understanding of chemistry by drawing structural formulae, identifying functional groups, writing chemical equations or working out formulae.
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
Two bottles containing different white crystals have lost their labels. The Science teacher says that one of them contains potassium chloride (KCl) and the other glucose (C6H12O6).
Using your knowledge of Chemistry, describe how you would decide which bottle is which. (3)
You should have recognised that one of the compounds has Ionic bonding and the other has covalent. When being asked to compare two compounds, this should be the first thing you check, as the way in which atoms join together will determine the properties of that compound.
Your answer could have included:
Definition of Ionic and Covalent
Conductivity, solubility, state at room temp (Difference between molecular and network)
Other possibilities include:
Salt formation – neutralisation reactions
Energy released from fuels
A student was measuring the pH of various solutions and concluded that only acids contained hydrogen ions and only alkali contained hydroxide ions.
Using your knowledge of chemistry comment on the statement made (3 marks)
The labels have dropped off three bottles containing organic compounds. The chemistry technician has asked a National 5 chemistry class to identify these compounds.
Using your knowledge of chemistry, comment on how would the class could identify the alcohol, alkene and carboxylic acid.
Using your knowledge of Chemistry describe how 4 metals could be placed in order of reactivity (3)
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.