12.3. Chromatography
A subsection of Chemistry, 0620, through 12. Experimental techniques and chemical analysis
Listing 10 of 117 questions
A student placed a crystal of purple potassium manganate(on a fi lter paper which had been soaked in water. After 5 minutes, a purple colour had spread out from the crystal. After 30 minutes, the purple colour had spread further out. crystal of potassium manganate(at the start after 5 minutes after 30 minutes wet filter paper Use the kinetic particle theory to explain these observations. Describe the closeness and motion of the particles in a crystal of potassium manganate(. closeness motion Mixtures of dyes can be separated by paper chromatography using the apparatus shown below. base line On the diagram above • draw a line to show the solvent level at the beginning of the experiment, • put a cross to show where the spot of dye mixture is placed at the beginning of the experiment.
0620_m15_qp_22
THEORY
2015
Paper 2, Variant 2
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Lavandulol is a compound found in lavender flowers. The structure of lavandulol is shown. C C H CH3 CH3 CH2 CH2 CH2 CH3 C O H C H On the diagram, draw a circle around the alcohol functional group. How many carbon atoms are there in one molecule of lavandulol? What feature of the lavandulol structure shows that it is unsaturated? Describe a test to show that lavandulol is unsaturated. test result Lavandulol can be extracted from lavender flowers. The following statements are about the procedure for extracting lavandulol. A Stir the mixture and leave it for a few hours. B Filter off the solid from the solution. C Distil the solution. D Add solvent to the ground up lavender flowers. E Grind up the lavender flowers. Put the statements A, B, C, D and E in the correct order. The first one has been done for you. E Chromatography can be used to separate the coloured pigments extracted from lavender flowers. The apparatus used is shown. solvent chromatography jar cover chromatography paper baseline After a few minutes the solvent vapour fills the whole chromatography jar. Use the kinetic particle model to explain this. Three different dye mixtures, P, Q and R, were placed on a sheet of chromatography paper. Two pure dyes, X and Y, were also placed on the same piece of chromatography paper. The experiment was carried out and the results are shown. P Q R X Y Where were the dyes placed on the chromatography paper at the start of the experiment? Which dye mixture contained the greatest number of dyes? Which dye mixture contained both dye X and dye Y?
0620_m17_qp_32
THEORY
2017
Paper 3, Variant 2
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Questions Discovered
117