What students find difficult
The key areas of difficulty encountered by students in the study of rates of reaction are:
- manipulating equipment
- accurately recording data
- drawing graphs of the data
- determining the rate at specific points during a reaction
- in investigations, choosing the correct method for monitoring a reaction
- interpreting rates graphs
In order to overcome these difficulties students need to have ample opportunity to select equipment, record and manipulate data.
Students should also be provided with experimental data generated from the work of others and encouraged to make judgements and draw conclusions.
For more help with tackling these with students you may wish to look at the Maths skills course pages as follows:
For example, when looking at the rate of reaction between calcium carbonate and hydrochloric acid students typically collect the gas by displacement in an upturned measuring cylinder.
[INSERT RATE_CI_05_ima]
What problems do you think might be encountered here?
Reading the scale on the measuring cylinder as it is upside down, putting the bung in at the correct time, securing the measuring cylinder.
How might you overcome these difficulties?
1. Allow students to practise gas collection techniques. 2. Copy a set-up from a diagram or displayed apparatus. 3. Introduce the use of gas syringes.