Chromatography

The diagram shows the paper chromatograms of four substances, W, X, Y, and Z.

Which two substance are pure?

• W and X

• W and Y

• X and Y

• Z and X

A student is investigating a colored mixture using chromatography.

Where should he place the coloured mixture?

• in the solvent

• just above the pencil line

• just below the pencil line

• on the pencil line

Chromatography is used to fin out if a banned dye, P, is present in foodstuffs. The result are shown in the diagram. Which foodstuff contains P?

• A

• B

• C

• D

Fruit drink colored orange contains a dissolved of red and yellow coloring coloring agents. One of these coloring agents is suspect of being illegal. Which method could be used to show the presence of this illegal coloring agent?

• Filtration

• Simple distillation

• Evaporation

• Chromatography

Food colorings contain one or more food dyes. A student used paper colorings (E, F, and G) and one unknown food coloring (H) on the chromatography. The diagram shows the appearance of the paper before and after her experiment. How many food dyes are there in food colouring E?

• 1

• 2

• 5

• 6

Food colorings contain one or more food dyes. A student used paper colorings (E, F, and G) and one unknown food coloring (H) on the chromatography. The diagram shows the appearance of the paper before and after her experiment. How many food dyes are there in food colouring G?

• 1

• 2

• 5

• 6

Which of the statement about paper chromatography is correct?

• A solvent is needed to dissolve the paper

• Paper chromatography separates mixtures of solvent

• The solvent should cover baseline

• The baseline should be drawn in pencil

The chromatogram obtained from four mixtures of dyes, P, Q, R, and S, is shown.\What is the total number of different dyes identified in the four mixtures?

• 3

• 4

• 5

• 8

Chromatography experiments are carried out on four substance, P, Q, R, and S. The same solvent is used in each experiment. The resulting chromatograms are shown below. Which statement is not correct?

• P and Q are pure substances

• P and R are different substances

• R and S are pure substances

• S is a mixture of substance

chromatography separates the mixture of dyes on the basis of their ----------------------------

• density
• solubility
• gravity
• boiling point