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

A teacher mixed aluminium and iodine powder, and added a drop of water.

A teacher mixed aluminium and iodine powder, and added a drop of water.

The reaction shown by the equation below occurred.

2Al(s) + 3I2(s) → 2AlI3(s)

Explain what is shown by the formulae in the equation, and by the equation itself. [6 marks]

The following are valid 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.

  • The reactants are aluminium and iodine
  • Iodine exists as molecules, each made up of two iodine atoms
  • The product is aluminium iodide
  • In aluminium iodide there are three atoms of iodine for every one atom of aluminium
  • Two atoms of aluminium react with (3 × 2) = 6 atoms of iodine
  • There are the same number of atoms of each element before and after the reaction

Sample question 2 - Foundation

Question

State the law of conservation of mass, and explain why some reactions may appear to involve a change in mass. [6 marks]

The following are valid 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.

  • In a chemical reaction no atoms are lost or made.
  • The mass of products is equal to the mass of reactants.
  • Sometimes the mass appears to increase.
  • This is often because a solid reactant has joined to a gas from the air.
  • Sometimes the mass appears to decrease.
  • This is often because one of the products is a gas which is released to the air.

Sample question 3 - Higher

Question

Explain why 1 mol of aluminium sulfate has a number of ions that is five times greater than the number of atoms in 1 mol of aluminium metal.

Include a chemical formula in your answer.

The value of the Avogadro constant is 6.02 × 1023/mol. [6 marks]

The following are valid 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.

  • The formula of aluminium sulfate is Al2(SO4)3.
  • There are 2 mol of aluminium ions and 3 mol of sulfate ions/a total of 5 mol of ions in 1 mol of aluminium sulfate.
  • There is 1 mol of aluminium atoms in 1 mol of aluminium metal.
  • The Avogadro constant is the number of particles in one mole of a substance.
  • 1 mol of aluminium sulfate has 5 mol × 6.02 × 1023/mol = 3.01 × 1024 ions.
  • 1 mol of aluminium metal has 1 mol × 6.02 × 1023/mol = 6.02 × 1023 atoms.

Sample question 4 - Higher

Question

A student reacts calcium carbonate with hydrochloric acid.

Suggest how she can use the apparatus in the list below to show that the mass of the contents of the beaker decreases.

Apparatus:

  • beaker
  • balance
  • spatula
  • watch glass

[6 marks]

  • Place the watch glass on the balance.
  • Use the spatula to place some calcium carbonate on the watch glass and record the mass of calcium carbonate.
  • Place a beaker of hydrochloric acid on the balance. Record the mass of acid + beaker.
  • Calculate the total mass of reactants + beaker.
  • Add the calcium carbonate to the acid in the beaker on the balance.
  • Record the mass when the effervescence finishes.