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9701/43

Chemistry 9701/43 — October/November 2014

Cambridge A-Level · Structured Questions · worked solutions for every part, with the mark scheme

9
questions
100
marks
120
minutes

Topics Nitrogen Compounds · Introduction to A Level Organic Chemistry · Equilibria · Analytical Techniques · Group 2 · Chemical Energetics · +7 more

Q1Group 2Chemical EnergeticsFree sample
(a)

Chlorine exists naturally as a mixture of two isotopes, 35Cl^{35}\text{Cl} and 37Cl^{37}\text{Cl}, in the abundance ratio of 3:13:1.

The mass spectrum of chlorine consists of five peaks.

(i)

Suggest the mass numbers for these five peaks and the identities of the species responsible.

mass numberformula of species
(ii)

Predict the ratios of the abundances of the three species with the highest mass numbers.

ratio of abundances =

4M
(b)

Strontium chloride, SrCl2\text{SrCl}_2, can be used to produce a red colour in fireworks.

(i)

Draw the ‘dot-and-cross’ diagram for strontium chloride. Show outer shell electrons only.

(ii)

Use the following data, together with relevant data from the Data Booklet, to calculate a value for the lattice energy of strontium chloride. You may find it helpful to construct a Born-Haber cycle.

electron affinity per mole of chlorine atoms−349 kJ mol−1-349\text{ kJ mol}^{-1}
standard enthalpy of atomisation of Sr(s)\text{Sr(s)}+164 kJ mol−1+164\text{ kJ mol}^{-1}
standard enthalpy of formation of SrCl2(s)\text{SrCl}_2\text{(s)}−830 kJ mol−1-830\text{ kJ mol}^{-1}

lattice energy = .................................. kJ mol−1\text{kJ mol}^{-1}

5M
(c)

Strontium nitrate, Sr(NO3)2\text{Sr(NO}_3)_2, can also be used to produce a red colour in fireworks.

(i)

Strontium nitrate can easily be prepared from strontium carbonate, SrCO3\text{SrCO}_3.

Suggest an equation for this preparation of strontium nitrate.

(ii)

Write an equation for the reaction that occurs when strontium nitrate is heated.

2M
(d)

Describe and explain the trend in the thermal stabilities of the nitrates of the Group II elements.

3M

The rest of this paper

8 more questions
  • Q2Electrochemistry · Reaction Kinetics8M
  • Q3Transition Elements14M
  • Q4Equilibria · Nitrogen Compounds · Introduction to A Level Organic Chemistry12M
  • Q5Introduction to A Level Organic Chemistry · Hydroxy Compounds · Nitrogen Compounds · Carboxylic Acids and Derivatives · Hydrocarbons12M
  • Q6Introduction to A Level Organic Chemistry · Nitrogen Compounds10M
  • Q7Equilibria · Analytical Techniques11M
  • Q8Introduction to A Level Organic Chemistry · Analytical Techniques10M
  • Q9Polymerisation · Nitrogen Compounds9M
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