Reacting Ratios

These diagnostic questions and response activities (contained in the zip file) support students in being able to:

• Use the concept of ratio to identify the molecule diagrams that correspond to a given balanced chemical equation.
• Recognise that a chemical equation does not account for the number of elementary entities of a reactant that is in excess.
• Recognise that a very large number of molecules react in the ratio shown by the balanced chemical equation for the reaction.
• Recognise that when a chemical equation includes the formula of an ionic compound, the elementary entity in the reacting ratio is the formula unit.
• Recognise that measured mass may be used to determine the number of moles of the limiting reactant, and hence the mass of product that may be formed.

The resources include details of common misconceptions and a summary of the research upon which the resources are based.

Download the zip file for all the questions and activities.

More resources like this can be found on the BEST webpage:  Best Evidence in Science Teaching