Chemical Analysis Flashcards
What is a formulation?
Mixtures with specific amounts of ingredients designed to do a particular job
What is a pure substance?
A substance that contains one chemical
Elements: pure (don’t have to be)
Compounds: pure (don’t have to be)
Mixtures: Never pure
What are the properties of pure and impure substances?
Pure:
They have fixed melting and boiling points
Impure:
Have varying melting and boiling points
normally lower melting points and increase boiling points
Stationary phase (chromatography)?
paper
The more strongly the part of the mixture is attracted to the paper the less far it moves up the paper
Mobile phase (chromatography)?
solvent
The more strongly the part of the mixture is attracted to the solvent the further it moves up the paper
What is the equation for Rf values?
distance travelled by substance / distance travelled by solvent
What colour does LITHIUM go in a flame test?
CRIMSON
What colour does SODIUM go in a flame test?
YELLOW
What colour does POTASSIUM go in a flame test?
LILAC
What colour does CALCIUM go in a flame test?
BRICK RED
What colour does COPPER go in a flame test?
GREEN
Precipitation reaction
2 solutions mixed with sodium hydroxide, solid forms and goes cloudy (precipitate)
What colour precipitate does ALUMINIUM give?
WHITE
What colour precipitate does CALCIUM give?
WHITE
What colour precipitate does MAGNESIUM give?
WHITE
What colour precipitate does COPPER give?
BLUE
What colour precipitate does IRON(2) give?
GREEN
What colour precipitate does IRON(3) give?
BROWN
Testing for anions?
Sodium carbonate: add HCL
Sodium sulphate: add mixture of barium chloride and HCL
Sodium chloride, bromide and iodide: add mixture of silver nitrate and nitric acid
Reaction of testing for anions?
Carbonates: fizzes and bubbles
Sulphates: WHITE precipitate
Chorides: WHITE precipitate
Bromide: CREAM precipitate
Iodide: YELLOW precipitate
Advantages of instrumental analysis?
Time saving
Improvement in accuracy
Improvement in sensitivity
Fast decisions
Disadvantages of instrumental analysis?
Costly
Quality depends on type of instrument
Specialised training is required
Frequently need to check results
