Chemical Analysis Flashcards
Flame Emission Spectroscopy
An example of an instrumental method used to analyse metal ions in solutions
- the sample is put into a flame and the light given out is passed through a spectroscope -> the output is a line spectrum that can be analysed to identify the metal ions in the solution and measure their concentration
Flames Tests
Lithium -> crimson
Sodium -> yellow
Potassium -> lilac
Calcium -> orange-red
Copper -> green
Carbonate test
Bubble through limewater and turns cloudy
Metal hydroxides test
Add NaOH:
Copper (II) -> blue precipitate
Iron (II) -> green precipitate
Iron (III) -> brown precipitate
Aluminium, calcium and magnesium produce a white precipitate
Aluminium dissolves in excess NaOH
Gas tests
Hydrogen: lit splint over a test tube produces a squeaky pop
Oxygen: glowing splint in test tube relights
Carbon dioxide: bubble through limewater turns cloudy
Chlorine test: damp litmus paper turns bleached
Sulfate test
Add dilute HCl then barium chloride:
White precipitate is formed if sulfate ions are present
Halides test
Add nitric acid then silver nitrate:
Chloride -> white precipitate
Bromide -> cream precipitate
Iodide -> yellow precipitate
What tests do you include in a question that talks about chemical tests
Anything BUT not flame tests
Pure substance
A single element or compound not mixed with any other substance
Formulation and examples
A mixture that has been designed as a useful product
-> fuels, cleaning agents, medicines, alloys
How does paper chromatography separate mixtures
- As the solvent soaks up the paper, it carries the mixtures with it
- Different components of the mixture will move at different rates
- This separates the mixture out
Stationary and mobile phase
Stationary phase: chromotapgehy paper
Mobile phase: solvent
Instrumental methods
- used to identify elements and compounds
- accurate, sensitive and rapid
