Six-mark questions

Six-mark questions are extended open response questions. These require longer answers than the structured questions that have fewer marks. It is wise to plan your answer first by making some notes. This will help you to include all the key points.

To gain full marks, you need to:

  • support explanations using scientific knowledge and understanding
  • use appropriate scientific words
  • write clearly and link ideas in a logical way
  • maintain a sustained line of reasoning

Six-mark questions often use these command words:

  • Describe means you should recall facts, events or processes accurately. You might need to give an account of what something looked like, or what happened.
  • Explain means you need to make something clear, or state the reasons for something happening.
  • Compare means you need to describe similarities and differences between things. If you are asked to compare X and Y, write down something about X and something about Y, and give a comparison. Do not just write about X only or Y only.
  • Evaluate means you must use information supplied, or your own knowledge, to consider the evidence for and against or to identify strengths and weaknesses. You must then complete your answer with a conclusion, stating which is better and why, for example.

Six-mark questions may be synoptic questions, which bring together ideas from two or more topics. For example, a question about fertilisers could include ideas about covalent substances, acids and alkalis, chemical calculations, and effects on the environment.

The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks, but you do need to write in sentences, linking them logically and clearly.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

Sample question 1 - Foundation

Question

You are provided with four solids which are soluble in water. Some of them dissolve during an exothermic reaction, and some dissolve during an endothermic reaction. Describe how you would identify which dissolving process absorbs and releases the most energy.

Your description should include a list of apparatus or a labelled diagram, how you will make the investigation a fair test, and how you would interpret the results. [6 marks]

The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.

Apparatus:

  • Polystyrene cup or (glass) beaker
  • Thermometer
  • Top pan balance
  • Measuring cylinder

Method (including fair testing):

  • Measure the same volume of water into the cup
  • Measure the same mass of solid
  • Record the temperature of the water
  • Add the solid and stir until dissolved
  • Record the maximum or minimum temperature

Interpretation of results:

  • Calculate the temperature difference for each solute
  • Temperature increases mean exothermic reactions/temperature decreases mean endothermic reactions
  • Largest temperature changes mean the most exothermic or endothermic reactions

Sample question 2 - Foundation

Question

Compare exothermic and endothermic reactions.

In your answer, explain the differences between exothermic and endothermic reactions and give examples of each type of reaction. [6 marks]

  • An exothermic reaction transfers energy to the surroundings..
  • ...so the temperature of the surroundings increases.
  • An endothermic reaction takes in energy from the surroundings..
  • ...so the temperature of the surroundings decreases.
  • Exothermic reactions include combustion and neutralisation.
  • Endothermic reactions include thermal decompositions / the reaction of citric acid and sodium hydrogencarbonate.

Sample question 3 - Higher

Question

The diagram below shows the reaction between ethene and chlorine and is similar to the reaction between ethene and bromine.

Molecular structure of dichloroethane.

"The more energy levels (shells) of electrons an atom has, the weaker the covalent bonds that it forms."

Use the above statement to predict and explain how the overall energy change for the reaction of ethene with chlorine will differ from the overall energy change for the reaction of ethene with bromine. [6 marks]

The following are vaild points that could be included in your answer. It is important that you do not bullet point your answer but write your sentences in full.

Size and strength:

  • Chlorine atoms have fewer electron energy levels/shells
  • Chlorine atoms form stronger bonds
  • Cl−Cl bond stronger than Br−Br
  • C−Cl bond stronger than C−Br

Energies required:

  • More energy required to break bonds with chlorine
  • More energy given out when making bonds with chlorine
  • Overall energy change depends on sizes of energy changes

Conclusions:

  • If C−Cl bond changes more, then less exothermic
  • If C−Cl bond changes more, then more exothermic
  • We can't tell how overall energy change will differ as we do not know which changes more.