C12 - Chemical Analysis Flashcards
mnumonic device to remember metal ions and their colours in a flame
Lions Chase Small Cats / Kittens
it is written in ‘rainbow’ order (red to lilac)
list:
colour of positive metal ions in a flame
5 examples
- Lithium - crimson
- Calcium - orange-red
- Sodium - yellow
- Copper - green
- Potassium - lilac
list:
metal ions which make white precipitates and if they dissolve or not
sodium hydroxide test, 3 examples
- Aluminium - dissolves in excess sodium hydroxide solution
- Calcium - no change in excess sodium hydroxide solution
- Magnesium - no change in excess sodium hydroxide solution
list:
metal ions which make non-white precipitates
sodium hydroxide test
- Copper - blue
- Iron (ii) - green
- Iron (iii) - brown
what two tests can be performed on cations
metal ions
- flame tests
- sodium hydroxide precipitate tests
define:
cation
positively charged particle
define:
anion
negatively charged particle
describe:
test for carbonate ions
CO3 2-
- Add a few drops of dilute hydrochloric acid
- Bubbles are produced if carbonate ions are present
- Confirm that the gas is carbon dioxide - limewater turns milky/cloudy.
describe:
test for sulfate ions
SO4 2-
- Add a few drops of dilute hydrochloric acid
- Add a few drops of barium chloride solution
- A white precipitate forms if sulfate ions are present.
describe:
test for halide ions
- Add a few drops of dilute nitric acid
- few drops of silver nitrate solution
- observe the colour of any precipitate formed
list:
colour of precipitate from halide ions
- Chloride - white
- Bromide - cream
- Iodide - yellow
define
formulation
a mixture that is made up of exact ratios of substances
define
fixed point
the boiling/melting point of pure substances