IG Chapter 6 Chemical analysis

A student carries out an investigation on different plant extracts using paper chromatography. The experimental set-up he uses is shown below. Where should he place the samples of plant extract?

• On the pencil line

• Below the pencil line in the solvent

• Exactly 1 cm above the pencil line

• Exactly 1 cm below the pencil line

Paper chromatography was used to determine if a banned preservative, X, is present in four samples obtained from four different packaged foods labelled A, B, C and D. The results of the analysis of the foodstuffs are shown in the diagram below. Which foodstuff contains X?

• A

• B

• C

• D

The diagram below illustrates the experimental set-up to carry out distillation. What are the correct labels for points A and B on the condenser?

• A: water in, B: water in

• A: water in, B: water out

• A: water out, B: water in

• A: water out, B: water out

A student performs a technique using the apparatus shown. Which separation technique has the student performed?

• Crystallisation

• Evaporation

• Distillation

• Filtration

Rocksalt is the mineral form of sodium chloride. It is known to commonly contain sodium chloride and sand along with other trace impurities. A combination of physical changes and separation techniques can be used to produce higher purity sodium chloride and sand. What is the correct order of physical changes and separation techniques to separate sodium chloride and sand?

• Melting, filtering, crystallising

• Melting, filtering

• Dissolving, filtering, crystallising

• Dissolving, crystallising

A substance was analysed and was found to have a boiling point of 450 °C. At room temperature it is a soft grey solid. Which temperature could be the melting point of a pure sample of the substance?

• -12 °C

• 56 °C to 72 °C

• 250 °C to 275 °C

• 142 °C

Solid P melts at exactly 60^oC and boils at exactly 310^oC. Solid Q dissolves in ethanol and shows a green colour and a yellow colour when analysed using paper chromatography. Which row is correct?

• A

• B

• C

• D

A student has performed an experiment which produced a precipitate. She correctly chooses to separate the precipitate using the process of filtration. She prepares the filter paper to be placed into the funnel by folding it as shown below. Which diagram correctly illustrates the filter paper at stage 3?

• A

• B

• C

• D

The diagram below shows the apparatus a student used to separate a product from a reaction mixture. What did the mixture contain?

• Aqueous sodium chloride and unreacted solid catalyst

• Water and ethanol

• Water and oil

• Aqueous sodium chloride and oil

A yellow solid, W is soluble in water. Which method of separation is most commonly used to obtain the solid W from an aqueous solution?

• Neutralisation

• Chromatography

• Distillation

• Crystallisation