Experimental Design and Separation IGCSE QB

Dyes are coloured substances.

The chromatogram of substance X and four different dyes, 1, 2, 3 and 4, is shown.

Substance X contains only two of the dyes 1, 2, 3 and 4.

Which two dyes are present in substance X?

• 1 and 2

• 1 and 4

• 2 and 3

• 3 and 4

Which piece of apparatus is used to measure exactly 21.50 cm³ of dilute sulfuric acid?

• beaker

• burette

• measuring cylinder

• volumetric pipette

Which row shows an advantage and a disadvantage for the stated apparatus used in a titration?

• A

• B

• C

• D

Sample M contains calcium carbonate and sodium nitrate.

The result of adding water to M, stirring and filtering is shown.

No chemical reaction occurs.

Which terms describe M, calcium carbonate and aqueous sodium nitrate?

• A

• B

• C

• D

A mixture containing an aqueous salt, sand and hot water is stirred.

The mixture is then poured into the apparatus shown.

What is X?

• a filtrate only

• a residue only

• a solute only

• a solvent only

A scientist uses a titration to calculate the concentration of acid in a sample of lemon juice. A measured volume of aqueous lemon juice and a few drops of an indicator are added to a flask. The aqueous lemon juice is then titrated against 0.1mol.dm³ aqueous sodium hydroxide. Which piece of apparatus is used to add the aqueous sodium hydroxide to the flask?

• a burette

• a delivery tube

• a measuring cylinder

• a volumetric pipette

Which row shows how the boiling point and the melting point of water change when a soluble impurity is added to the water?

• A

• B

• C

• D

Which piece of apparatus can only measure a single fixed volume?

• a 250 cm³ beaker

• a 50 cm³ burette

• a 100 cm³ measuring cylinder

• a 25 cm³ volumetric pipette

The chromatogram of substance S is shown.

Some distances, W, X, Y and Z, are labelled on the diagram.

How is the R_f value of substance S calculated?

Some information about solid silver chloride and solid sodium chloride is shown.

- Silver chloride and sodium chloride do not dissolve in kerosene.

• - Silver chloride is insoluble in water, but sodium chloride is soluble in water.

• - The boiling point of silver chloride is 1547 ^oC and the boiling point of sodium chloride is 1413 ^oC.

• Which processes are used to separate a mixture of solid silver chloride and sodium chloride?

• add kerosene, stir and then filter

• add water, stir and then filter

• add water, stir and then leave to crystallise

• add water, stir and then perform fractional distillation