purity, formulations and chromatography Flashcards
(31 cards)
what are formulations?
mixtures of different ingredients that creates a useful product that contains advantageous characteristics (eg, acetone (nail polish remover))
what is a pure substance?
a single element or compound not mixed
describe what chromatography is for?
a laboratory technique for separating mixtures
what can happen if the chromatography paper touches the sides of the glass beaker?
capillary action, will spread out unevenly
what is the equation for the Rf value?
distance moved by substance/distance moved by solvent
what’s the stationary phase?
the chromatography paper (doesn’t move)
what is the mobile phase?
the solvent (moves)
why isn’t water always the only solvent used in this practice?
because not all substances dissolve in water so other solvents are used
why may a lid be used?
because different solvents evaporate at different temperatures and they could evaporate while the chromatogram is developing as they may be more volition
what is the test for oxygen?
manganese oxide+ hydrogen peroxide
light a splint and blow it out then put it into the test tube
it will re-light if oxygen is present
what is the test for hydrogen?
magnesium+hydrochloric acid
put a bung on top of test tube and when ready put a lit splint into the tube
it will make a squeaky pop noise and put out the fire
what is the test for carbon dioxide?
sodium carbonate+hydrochloric acid in one test tube and lime water in another
quickly using a pipette transfer the co2 produces into the limewater
it should go cloudy
what is the test for chlorine?
damp litmus paper will bleach white
what colour does lithium go in the flame test?
crimson/ruby red
what colour does sodium go in the flame test?
yellow
what colour does potassium go in the flame test?
lilac
what colour does calcium go in the flame test?
red/orange
what colour does copper go in the flame test?
green
describe the flame test?
pour about 1cm depth of chloride solutions into test tubes and dip a wet splint into each of the solutions and then put in the roaring blue flame and observe
describe the carbonate test
- 1cm depth of all the sodium solutions and then limewater in the last one
- add hydrochloric acid to each one at a time and using a pipette transfer gases produced to the lime water
describe the sulphate test
- 1cm depth of each sodium solutions into all five test tubes
- then add HCL and barium chloride (1cm depth)
- record results
describe the halide test
- 1cm depth of each sodium solutions into all five test tubes
- add a few drops of nitric acid and silver nitrate solution
- record results
how do you identify Ions?
add sodium hydroxide to the different metals and it will create a precipitate
what precipitate does magnesium produce in the identifying ions test?
white
