C12: Chemical Analysis Flashcards
what is a pure substance?
single element or compound, not mixed with any other substance
how do you know its a pure substance?
melt/boil at specific temps
- mixtures have range of MPs and BPs
what is a formulation?
mixture that has been desiged as a useful product
- made my mixing components in carefully measured quanities to ensure product has required properties
examples of formulations ?
fuels, cleaning agents , paints amnd medecines
process of chromotography?
- pencil line drawn on chromotography paper/ spots of sample placed on it
- paper lowered into solvent , making sure pencil line is above solvent
- different substance have differnt solubility so travel at different rates (high solubility-travel further)
how can u identify if substance is pure or not from chomotography?
pure substance only has one spot on chromotogram
- mixtures have multiple
how to calculate Rf value?
distance moved by substance/distance moved by solvent
flame test for
Lithium?
crimson
flame test for
sodium
yellow
flame test for
potassium
lilac
flame test for
calcium
orange-red
flame test for
copper
green
effect of adding metal NaOH to
aluminium. calcium, magnesium
white precipitate
(only aluminium’s precipitate dissolves when excess NaOh is added)
effect of adding metal NaOH to
copper
blue precipitate
effect of adding metal NaOH to
iron II/iron III
iron II - green precipitate
iron III - brown precipitate