chemistry topic 8 Flashcards
what is a pure substance
a single element or compound
what is a formulation
mixture designed as a useful product - made by mixing the
components in carefully measured quantities
what are some examples of formulations
paints
medicines
fertilisers
what does chromatography do
separates soluble mixtures from a solvent
what is the formula for Rf
Rf = distance moved by substance (dye) / distance moved by solvent
what does the Rf value of a dye depends on
The solubility of the dye in the solvent
The attraction of the dye to the paper.
If a dye travels further up the paper:
It is more soluble in the solvent
has less attraction to the paper.
how to test for oxygen
test: glowing splint
result: re-lights
how to test for hydrogen
test: burning splint
result: squeaky pop
how to test for carbon dioxide
test: bubble through limewater
result: limewater goes cloudy
how to test for chlorine
test: damp litmus paper
result: Bleached – blue to white
how to test for lithium ions
flame test: crimson flame
how to test for sodium ions
flame test: yellow flame
how to test for potassium ions
flame test: lilac flame
how to test for copper ions
flame test: Green flame
add sodium hydroxide: blue precipitate
how to test for calcium ions
flame test: orange-red flame
add sodium hydroxide: white precipitate (does not dissolve when more added)
how to test for magnesium ions
add sodium hydroxide: white precipitate (does not dissolve when more added)
how to test for aluminium ions
add sodium hydroxide: white precipitate (does dissolve when more added)
how to test for iron (ii) ions
add sodium hydroxide: green precipitate
how to test for iron (iii) ions
add sodium hydroxide: brown precipitate
how to test for sulfate ions
add barium chloride with hydrochloric acid: white precipitate
how to test for carbonate ions
add dilute acid: bubbles of gas that turn limewater cloudy
how to test for chloride ions
add silver nitrate with nitric acid:
white precipitate
how to test for iodine ions
add silver nitrate and nitric acid: yellow precipitate
how to test for bromide ions
add silver nitrate with nitric acid: cream precipitate
what are the benefits of Elements and compounds being detected and identified
using Instrumental methods
Accurate
Sensitive
Rapid
what is Flame emission spectroscopy used for
its used to identify and
measure concentrations of metal ions in solution.
how is Flame emission spectroscopy done
Put sample into flame.
Light given out is passed through a spectroscope.
Each metal has their own patterns of bands which allows them to be identified as being present in the solution.
