Chemical Analysis is all about working out what something is. Analytical Chemistry is a branch of Chemistry used in many different setting. Forensic Chemistry may be the obvious one but it is also used in sports drug testing, in pharmaceutical companies to check they have the correct product and that it is pure, water treatment companies and anywhere you need to know the identity of a chemical.
Pure in a Chemistry sense is something that only consists of 1 element or compound. It is NOT a mixture. However sometimes products are deliberately sold to us as impure. These are formulations. Extra ingredients are added to enhance the product such as colouring, flavouring, something to improve texture etc. It is important that you can recognise these.
The easiest way to determine is a sample is pure is to test it melting or boiling point. Every substance has a very exact melting and boiling point (0 and 100 degrees C for water) and if you determine this very accurately you will be able to see if it is pure or not by comparing your value to a database of these values. Salty water will boil at a higher temperature than pure water.
Once you know something is impure you may want to find out what is in it. This is where the required practical on Chromatography comes in. You must learn the method, why you draw a starting line in pencil, why and how you calculate Rf values and how you use standard samples to determine what is in your unknown sample. If you don’t know the answers to all these read the 100% sheets.
This section is only for those students studying for the Triple Award in Science.
Use the 100% sheet and LEARN ALL THE ION TESTS. Remember that you will need to do separate tests to find the Cation (positive ion) and the Anion (negative ion)
Review and Rate your Understanding
After revising the topic and completing the questions of the 100% sheet try the end of topic summary questions (answers given) and then print and complete the checklist to rate your understanding.
Have you learnt all the facts on the 100% sheet?
Have you completed the BBC Bitesize tutorial?
Have you been able to complete all the questions on the 100% sheet?
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