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ASChemistryEdexcelExam Questions4. Core Chemistry Practicals4.2 Inorganic & Organic Chemistry Core Practicals

Inorganic & Organic Chemistry Core Practicals (Edexcel AS Chemistry)

Exam Questions

35 mins5 questions
Easy
Medium
1a2 marks

Aqueous sodium carbonate and aqueous sodium sulfate are both colourless solutions.

Give the reagent and the observation to show the presence of carbonate ions.

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1b2 marks

Give the reagent and the observation to show the presence of sulfate ions.

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2a2 marks

An inorganic salt A contains one cation and one anion.
The results of two tests on salt A are shown in the table.

Test Observation
Add aqueous sodium hydroxide to solid A.
Warm the mixture.
Test any gas evolved with damp red litmus paper.		 A gas was evolved.
The gas turned red litmus paper blue.
Add dilute nitric acid followed by aqueous
silver nitrate to an aqueous solution of A.		 A cream precipitate formed.

Deduce the name of salt A.

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2b2 marks

Describe additional tests, with the results, that will confirm the identity of the anion in the cream precipitate.

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3a2 marks

Some alcohols can be oxidised by acidified sodium dichromate(VI), Na2Cr2O7.

Balance the ionic half-equation for the reduction of the dichromate(VI) ion.

Give the colours of all of the species involved, or state colourless if appropriate.

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3b2 marks

Reflux apparatus can be used to carry out the oxidation of alcohols.

i)
This Liebig condenser has been set up incorrectly. Add shading to the diagram to show the water in the condenser, illustrating the effect of the incorrect water flow.

(1)

q5bi-9cho-al-2-june-2018-qp-edexcel-a-level-chem

ii)
State how the granules prevent bumping.

(1)

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3c1 mark

The carboxylic acid shown can be produced by oxidation of an alcohol under reflux.

q5c-9cho-al-2-june-2018-qp-edexcel-a-level-chem

Which alcohol would be oxidised under reflux to produce this carboxylic acid?

  ☐ A 1,1-dimethylethanol
  ☐ B 2-methylpropan-1-ol
  ☐ C 2-methylbutan-1-ol
  ☐ D propan-2-ol

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3d2 marks

Using the apparatus for distillation instead of reflux is not an efficient way to produce ethanoic acid from ethanol. Explain why.

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1a3 marks

An ionic compound contains a metal cation and a non-metal anion in a 1 : 1 ratio, and water of crystallisation. The compound can be represented as MN.xH2O, where x is the number of moles of water of crystallisation per mole of MN.

A sample of MN.xH2O was dissolved in distilled water to produce a colourless solution, with a concentration of about 0.5 mol dm−3. 2 cm3 of the resulting solution was transferred to each of two test tubes.

The following tests were carried out to identify the ions present.

Test 1

 
i)
Addition of a few drops of a solution of barium chloride to one of the test tubes gave a white precipitate.
 
Identify, by name or formula, two possible anions that would give this result. 
(1)
 
ii)
Addition of 1 cm3 of dilute hydrochloric acid to the test tube in (a)(i) resulted in no further change.
 
Give the formula of the anion. 
(1)
 
iii)
What is the charge on the cation? 
(1)
  ☐ A +1
  ☐ B -1
  ☐ C +2
  ☐ D -2

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1b1 mark

Test 2

 A flame test on a sample of solid MN.xH2O gave no change in the flame colour.

 Give a possible identity of the cation, M. 

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1c
Sme Calculator4 marks

Heating the hydrated compound results in the formation of the anhydrous ionic solid MN by the following reaction: 

MN.xH2O (s) → MN (s) + xH2O (g)
 

Heating a sample of the hydrated compound reduced the mass to 48.9% of its original value.

 

Use this information and your answer to (a)(ii) and (b) to calculate the value of x.

 

[Note: If you have been unable to identify MN, you may use this hydrated compound, CoCl2.yH2O in which the sample reduced in mass to 54.6% of its original value. Use this information to calculate the value of y.] 

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2a3 marks

Halogenoalkanes react with water to produce alcohols and halide ions.


C4H9X + H2O → C4H9OH + X− + H+

Test tube experiments can be carried out to investigate the relative rates of these substitution reactions.

The halogenoalkanes 1‐chlorobutane, 1‐bromobutane and 1‐iodobutane can be used.

Some of the steps in these experiments are

  • each halogenoalkane is added to a different tube containing 1 cm3 of ethanol
  • the test tubes are placed in the same beaker of hot water
  • aqueous silver nitrate is added to each tube and the tubes are shaken
  • a precipitate forms in each tube.
i)
State the purpose of adding ethanol to each of the test tubes.
(1)
ii)
Give one reason why the test tubes were put in the same beaker of hot water.
(1)
iii)
Give one reason why the test tubes were shaken after the addition of aqueous silver nitrate.

(1)

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2b3 marks
i)
State how the halogen atom present in each halogenoalkane can be identified using observations from this experiment in (a).

(1)

ii)
Identify further reagents that can be added, including relevant observations, to confirm the identity of the halogen atom present in each halogenoalkane.
(2)

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2c6 marks

Outline the method for a test tube experiment, which expands on the steps in (a), to investigate how the rate of the substitution reaction depends on whether the halogenoalkane is primary, secondary or tertiary.

Your experiment should test a series of isomeric bromoalkanes reacting with water.

Your plan should include

  • the chemicals you will use
  • an outline of how the experiment will be carried out
  • the observations or measurements you will make and how you will interpret them.

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