CBC MOCK A LEVEL Chemistry 2007 Paper 3

(a)

(i)Briefly outline the principal oxidation states of either Nitrogen or Sulphur, giving the name wind formula of a compound for each oxidation number.

(ii)Describe and explain a `redox’ reaction showing how the oxidation state

of the element:

  • increases
  • decreases
  • increases and decreases.

 

 

(b) Nitric acid and sulphuric acid are compounds of nitrogen and sulphur respectively.

  • With the aid of equations, show how each of these acts as an oxidizing agent
  • Give and outline for the manufacture of any one of the acids. State with a reason in each case, two large scale uses of the acid chosen.
  • Describe how a dilute sample of either nitric acid or sulphuric acid may be prepared from a concentrated sample.

(25 marks)

 

2.(a) Distinguish between the following:

Homogeneous and heterogeneous catalysis’

Molecularity and order of a reaction.

Briefly describe a suitable experimental technique you would use to

follow the rate and hence determine the order of the reaction given

CH3COCH3(aq) + I2(aq) –>. CH3COgH2I(aq) + HI(aq)

 

(c)The collision and the transition state theories are used to interpret the rate of chemical reactions.

Outline the differences and similarities put forward by these theories.

(25 marks)

 

3).Discuss the different types of isomerism exhibited by all the compounds with the molecular formulae C5H100 and CH804. For each pair of isomeric molecules, describe a physiCal or chemical test to distinguish between them.

(25 marks)

 

 

 

Compare and contrast the physical and chemical properties of the s-block and group four elements of the periodic table under the following guidelines:

  • Atomic radius
  • Melting and boiling points
  • Acid base behaviour of the oxides. Mv5
  • Thermal stability and solubility of the chlorides.
  1. Ethanol (B.F. = 78°C) and propanone (B.P. = 56°C) when mixed together form a non-ideal mixture with a rise in ovell temperature.
  • Account for the rise in temperature.
  • Explain how an ethanol-propanone mixture deviates from ideal behaviour (Raoult’s law), giving an evidence that supports the

deviation.

(c) Describe the distillation process by which ethanol and propanone may – ‘he separated, explaining the use of the fractionating column (practical details are not needed).

 

 

 

6. Write short notes on the following, mentioning reagents, reaction conditions, products formed, mechanism, purification and precautions where necessary

 

  • Hydrolysis of 2-bromo-2-methylbutane
  • Nitration of benzene
  • Reduction of Nitrobenzene
  • Ammonolysis of benzoylchloride
  • Ozonolysis of 2-methylbut-2-ene

(25 mark)

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