IMPORTANT TIPS FOR CHEMISTRY PRACTICAL.

Evaluating evidence and procedures

When you evaluate your work you have to make judgments. You might start by making a short list of the criteria that you use to decide whether or not your practical work has been successful.

Your evaluation should always have two parts:

First you decide whether or not any results based on measurement are reliable and meaningful, or whether the outcomes of a preparation are adequate considering the methods used.

Second, you should review the practical techniques that you have used and decide whether they were the right ones to use; this should include comments on any results than seem anomalous.

Commenting on the reliability of data.

In a quantitative investigation your analysis should include an estimate of the overall uncertainty in your results.

Comment here on any anomalous results that do not seem to fit in with the rest of your measurement or observation. You should suggest an explanation for any anomalies that you have detected.

Comparing outcomes with expectations.

In some investigation you may be able to refer to published data in reference books, or other sources, which allow you to compare your findings with the generally accepted results.

Published description of chemical preparations often quotes the likely yield. This allows you to compare your percentage yield with the outcomes that can be reasonably expected. Sometimes the expectations are predictions based on theory. If so, you should discuss this whether or not you judge that your findings are consistent with your predictions.

Identifying possible improvements.

You should consider whether or not the method you used could have been improved, either by making minor modifications or by using a completely different approach. Here you can also refer to methods that you could not carry out with the usual range of equipment available in advanced chemistry laboratories. You might refer to other option such as the use of instrumental methods of analysis including the various types of spectroscopy.

NOTE: Ask for some help if you are stuck. It is better to lose a mark or two for assistance rather than ending with nothing because all your work is misguided.