Year 11 chemists have spent the last half-term (when not completing their mocks), studying chemical analysis. This involves using chemical techniques to identify unknown substances, essential in various applications from drug testing to environmental analysis. In class, the students have carried out tests for common gases, used flame tests to reveal which metal ions are present, used sodium hydroxide to detect even more metal ions and used various methods for identifying anions. The ultimate aim is for the students to have the knowledge and skills to be able to plan and carry out a range of experiments to identify an unknown chemical in a systematic way .
Unlike many aspects of chemistry, trends and patterns are less obvious in the results of these tests, so we’ve focused on memory techniques. This includes a variation on the mind palace method to remember the gas tests, word association for the flame test results and, where possible, linking results to trends that we have already looked at, such as in the test for halide ions.
To finish the unit, I showed the girls the screaming jelly baby demonstration, asking them to identify the metal present in the compound. The distinctive lilac flame produced allowed the girls to tell me that a potassium compound must have been present in the reaction.