Experimental Techniques and Chemical Analysis

Draw a labelled diagram to show the apparatus used in paper chromatography.

On your diagram show

• the solvent,
• where the mixture of metal ions and known samples of metal ions are placed at the start of the experiment.

Which of the metal ions, A–E, were present in the mixture?

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Calculate the $R_f$ value of metal ion A.

$R_f\text{ value} =$ ______

Suggest why a locating agent may need to be used.

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Aqueous ammonia is added slowly to aqueous copper(II) sulfate until the ammonia is in excess.

Describe what you would observe as the ammonia is added.

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Construct the ionic equation, with state symbols, for the reaction of aqueous copper(II) sulfate with aqueous sodium hydroxide.

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Describe how you would show that both ammonia and carbon dioxide are formed in this decomposition.

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Ammonium carbonate is soluble in water but zinc carbonate is insoluble in water.

Describe how you would prepare a sample of pure, dry zinc carbonate using a solution of ammonium carbonate.

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Describe how and explain why water can be separated from aqueous copper(II) sulfate by distillation.

In your answer include a description of distillation.

You may draw a labelled diagram.

Copper(II) sulfate can be prepared by heating excess copper(II) oxide with dilute sulfuric acid.

What method is used to separate excess copper(II) oxide from the reaction mixture?

______

A mixture of iron powder and zinc powder is added to excess sulfuric acid.

When the reaction stops, aqueous sodium hydroxide is added drop by drop to the reaction mixture until it is in excess.

Describe what you would observe during the addition of aqueous sodium hydroxide and explain the reactions taking place.

observations
______

explanations
______

Describe the chemical test for sulfur dioxide.

test = ______

observation = ______

Chlorine is bubbled through aqueous iron(II) chloride to form iron(III) chloride.

Explain, with the aid of equations, how aqueous sodium hydroxide can be used to distinguish between aqueous iron(II) chloride and aqueous iron(III) chloride.

Describe the chemical test for chlorine.

test = ______
observation = ______

Describe how you could show that aqueous ammonium nitrite contains ammonium ions.

Describe how a pure sample of aqueous ammonium nitrate can be prepared from dilute nitric acid.

Write the formula of gas B.

______

Write an ionic equation, including state symbols, for the formation of the green precipitate D.

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Suggest the name of reagent X and give the formula for the white precipitate E.

name of reagent X ______
formula of precipitate E ______

reacts with dilute nitric acid to form a gas that turns limewater milky

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reacts with warm aqueous sodium hydroxide to form a gas that turns damp red litmus paper blue

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reacts with dilute hydrochloric acid to give a gas that decolourises acidified potassium manganate(VII)

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Describe how the titration method is used to prepare a colourless solution of sodium sulfate.

Describe how a sample of pure sodium sulfate crystals can be made from aqueous sodium sulfate.