What is chromatography used to separate?An insoluble solid from a liquidTwo or more liquids with different boiling pointsDifferent substances dissolved in a liquidTwo or more different gases2Which of the following statements about paper chromatography is not true?Less soluble substances travel further up the paperSubstances are separated based on how attracted they are to each phaseThe stationary phase is the paperThe mobile phase is the solvent3What are Rf values useful for?To determine how much solvent to use in the chromatography procedureTo calculate how much paper to useTo identify unknown samples by comparing them with known samplesTo determine the number of different substances in a solvent4How is the Rf value of a substance calculated?Distance moved by substance divided by distance moved by solventDistance moved by solvent minus distance moved by substanceDistance moved by solvent divided by distance moved by substanceDistance moved by substance multiplied by distance moved by solvent5In the core practical ‘Paper chromatography to investigate the composition of ink’, a line is drawn at the bottom of the paper onto which spots of known ink colourings plus an unknown sample are placed. There are several key points to remember when setting up this practical. Which of the following is incorrect? The line must be above the water levelThe line must be in penThe sides of the paper must not touch the beakerThe sample spots should not spread out too far6On a paper chromatogram only one spot is produced. What does this tell you? The paper was not large enoughThe substance being separated is an impure substanceToo much solvent was usedThe substance being separated is a pure substance
Question
What is chromatography used to separate?An insoluble solid from a liquidTwo or more liquids with different boiling pointsDifferent substances dissolved in a liquidTwo or more different gases2Which of the following statements about paper chromatography is not true?Less soluble substances travel further up the paperSubstances are separated based on how attracted they are to each phaseThe stationary phase is the paperThe mobile phase is the solvent3What are Rf values useful for?To determine how much solvent to use in the chromatography procedureTo calculate how much paper to useTo identify unknown samples by comparing them with known samplesTo determine the number of different substances in a solvent4How is the Rf value of a substance calculated?Distance moved by substance divided by distance moved by solventDistance moved by solvent minus distance moved by substanceDistance moved by solvent divided by distance moved by substanceDistance moved by substance multiplied by distance moved by solvent5In the core practical ‘Paper chromatography to investigate the composition of ink’, a line is drawn at the bottom of the paper onto which spots of known ink colourings plus an unknown sample are placed. There are several key points to remember when setting up this practical. Which of the following is incorrect? The line must be above the water levelThe line must be in penThe sides of the paper must not touch the beakerThe sample spots should not spread out too far6On a paper chromatogram only one spot is produced. What does this tell you? The paper was not large enoughThe substance being separated is an impure substanceToo much solvent was usedThe substance being separated is a pure substance
Solution
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Chromatography is used to separate different substances dissolved in a liquid.
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The statement about paper chromatography that is not true is "Less soluble substances travel further up the paper".
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Rf values are useful for identifying unknown samples by comparing them with known samples.
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The Rf value of a substance is calculated by the distance moved by substance divided by distance moved by solvent.
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The incorrect point when setting up the practical 'Paper chromatography to investigate the composition of ink' is "The line must be in pen".
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If only one spot is produced on a paper chromatogram, it tells you that the substance being separated is a pure substance.
Similar Questions
Which statement about paper chromatography is correct?1 pointa. A solvent is needed to dissolve the paper.b. Paper chromatography separates mixtures of solvents.c. The solvent should cover the baseline.d. The baseline should be drawn in pencil
What is the principle of the paper chromatography ?a.Partitionb.Adsorptionc.A and Bd.None of the above
What is chromatography?a.A technique used to separate molecules on the basis of differences of solubility and adsorption properties.b.A simple technique used to separate solvent from solution.c.A simple technique used to separate solution of different concentration.d.A technique used to separate molecules on the basis of colour.Clear my choice
What is one of the advantages of carrying out chromatography?only coloured substances can be used for the experimentonly small amount of the sample is neededonly applicable to substances which are soluble in the solventcan only work on paper materials to form the chromatogram
According to the small size of the particle, which type of chromatographic separation is applicable?Question 4AnswerA.High- performance liquid chromatography (HPLC)B.Gel chromatographyC.Fast protein liquid chromatography (FPLC)D.Paper chromatography
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