URGENT Edexcel science revision (C2 9th June)Watch
1) explain why hydrogen is not in group 1? (2 marks)
2) How would you separate two Immiscible substances? (3 marks)
3) Explain how to separate the different components of air? (6 marks)
4) Describe the practical steps involved in producing a chromatogram for a dye? (6 marks)
2) Separating funnel; they'll separate into layers (the densest at the bottom). Use a tap on the bottom of the funnel to separate them individually.
3) Fractional distillation:
i: Filter air to remove dust
ii. Cool air to -200C -> CO2 freezes and is removed, water vapour condenses and is removed
iii. Heat the liquid air slowly in the fractioning column and it will separate out into 'layers' which leave through pipes
iv: Oxygen and argon leave together so another column is used to separate them
i. On paper, draw a pencil base line with crosses and labels for each substance
ii. add a drop of each substance to each cross on the baseline
iii. add the paper to a container of solvent (e.g. water, ethanol); the level of solvent must be below the baseline
iv: the solvent will travel up the paper, taking the substances with it and separating them into their different chemicals
[v: the Rf value of each chemical = distance travelled by substance / distance travelled by solvent]
Hope this helps!
Uses: maybe a possible question
> police are able to analyse samples of DNA to find suspects.
>analyse paints and dyes so that museums are able to mix exact copies of old paints and restore
>used for food standards to see if dyes in food are safe to consume.
You may also be asked about the Rf value this is the distance moved by the compound divided by the distance moved by the solvent
This is what the equation looks like remember it:
Distance moved by compound
-----------------------–-------------- = Rf value
Distance moved by solvent
Hope this helps