AS & A Level Chemistry - 9701 Paper 2 2014 Summer Zone 1

(a) Explain what is meant by the term ionisation energy.
........................................................................................................................................................ ................................................ ...................................................................................................................... ........................................................................................................................................................ [3]

(b) The first seven ionisation energies of an element, A, in kJ mol^-1, are
1012 1903 2912 4957 6274 21269 25398.
(i) State the group of the Periodic Table to which A is most likely to belong. Explain your answer.
........................................................................................................................................................ ................................................ .............................................................................................................. ................................................................................................................ ................................................ ...................................................................................................................... ........................................................................................................................................................ [2]
(ii) Complete the electronic configuration of the element in Period 2 that is in the same group as A.
1s² ........................................................................................................................................................ [1]

(c) Another element, Z, in the same period of the Periodic Table as A, reacts with chlorine to form a compound with empirical formula ZCl₂. The percentage composition by mass of ZCl₂ is Z, 31.13; Cl, 68.87.
(i) Define the term relative atomic mass.
........................................................................................................................................................ ................................................ .............................................................................................................. ................................................................................................................ [2]
(ii) Calculate the relative atomic mass, A_r, of Z.
Give your answer to three significant figures.
A_r of Z = ................................................ [2]

(d) The chlorides of elements in Period 3 of the Periodic Table show different behaviours on addition to water, depending on their structure and bonding.
(i) Write equations to show the behaviour of sodium chloride, NaCl, and silicon chloride, SiCl₄, when separately added to an excess of water.
NaCl ................................................ .............................................................................................. SiCl₄ ............................................................................................................................ [2]
(ii) State and explain the differences in behaviour of these two chlorides when added to water, in terms of their structure and the bonding found in the compounds.
........................................................................................................................ ................................................................................................................................................................................. ........................................................................................................................................................ ................................................ .............................................................................................................. ........................................................................................................................ ................................................ .............................................................................................................. ........................................................................................................................................................ [4]

(e) Sulfur reacts with fluorine to form SF₆. State the shape and bond angle of SF₆.
shape of SF₆ ...................................................................................................................... bond angle of SF₆ .................................................................................................................... [2]

The commonest form of iron(II) sulfate is the heptahydrate, FeSO_4·7H_2O. On heating at 90°C it loses some of its water of crystallisation to form a different hydrated form of iron(II) sulfate, FeSO_4·xH_2O.
3.40 g of FeSO_4·xH_2O was dissolved in water to form 250 cm³ of solution.
A 25.0 cm³ sample of this solution was acidified and titrated with 0.0200 mol dm⁻³ potassium manganate(VII).
In this titration 20.0 cm³ of this potassium manganate(VII) solution was required to react fully with the Fe²⁺ ions present in the sample.
(a) The MnO₄⁻ ions in the potassium manganate(VII) oxidise the Fe²⁺ ions in the acidified solution.
(i) Explain, in terms of electron transfer, the meaning of the term oxidise in the sentence above.
..................................................................................................................................................
.................................................................................................................................................. [1]
(ii) Complete and balance the ionic equation for the reaction between the manganate(VII) ions and the iron(II) ions.
MnO₄⁻(aq) + 5Fe²⁺(aq) + ........H⁺(aq) → ........(aq) + 5Fe³⁺(aq) + .......H₂O(l) [3]
(b) (i) Calculate the number of moles of manganate(VII) used in the titration. [1]
(ii) Use the equation in (a)(ii) and your answer to (b)(i) to calculate the number of moles of Fe²⁺ present in the 25.0 cm³ sample of solution used. [1]
(iii) Calculate the number of moles of FeSO_4·xH_2O in 3.40 g of the compound. [1]
(iv) Calculate the relative formula mass of FeSO_4·xH_2O. [1]
(v) The relative formula mass of anhydrous iron(II) sulfate, FeSO_4, is 151.8.
Calculate the value of x in FeSO_4·xH_2O. [1]

(a) In this question, K, L and M refer to a halogen atom or halide ion.
For each part question, read the information and complete the answer lines below.
(i) When concentrated sulfuric acid is added to solid NaK, white fumes are produced that turn damp blue litmus paper red. No other colour changes are observed.
identity of K = .....................................
equation for reaction .................................................................
explanation of observation ......................................................... ............................................................................................................. [3]
(ii) When silver nitrate solution is added to an aqueous solution of NaL, a precipitate forms that remains after the addition of concentrated ammonia solution.
identity of L = .....................................
colour of precipitate ......................................................................
equation for reaction ................................................................. [3]
(iii) $M_2$ is a liquid at room temperature with a boiling point higher than that of chlorine but lower than that of iodine.
identity of M = .....................................
explanation ......................................................................................... ............................................................................................................. ............................................................................................................. ............................................................................................................. [2]

(b) The diagram below is a simplified representation of a diaphragm cell.

(i) Identify each of the products.
B ..................................................................................................
C ..................................................................................................
D .................................................................................................. [3]
(ii) Give the equations for the two electrode reactions.
anode ..................................................................................................
cathode .............................................................................................. [2]

Alkanes and alkenes both react with bromine.

(a) Explain how and why bromine can be used to distinguish between an alkene and an alkane.
.....................................................................................................................................................................................
.....................................................................................................................................................................................
[2]

(b) The reaction of ethane with bromine forms a mixture of products.

(i) State the essential conditions for this reaction to occur.
...............................................................................................................................................................................
[1]

(ii) Give the full name of the mechanism of this reaction.
...............................................................................................................................................................................
[2]

(iii) Give the equation for a termination step that could occur, producing a hydrocarbon.
...............................................................................................................................................................................
[1]

(iv) Give the equation for one propagation step involved in the formation of dibromoethane
from bromoethane during this reaction.
...............................................................................................................................................................................
[1]

(c) The reaction of ethene with bromine forms a single product.

(i) Give the full name of the mechanism of this reaction.
.............................................................................................................................................................................
[2]

(ii) Complete the diagram below to illustrate this mechanism.
Include all relevant charges, partial charges, curly arrows and lone pairs.

[4]

(d) Chloroethene can be polymerised to form a polymer commonly known as PVC.
Draw a diagram of the structure of PVC including three repeat units.
[2]

(e) Chloroethane undergoes a series of reactions as shown in the diagram below.


(i) Give the reagent and conditions necessary for reaction 1.
..............................................................................................................................................................................
..............................................................................................................................................................................
[2]

(ii) Give the skeletal formula of product P.
..............................................................................................................................................................................
[1]

(iii) Give the displayed formula and the name of product Q.
..............................................................................................................................................................................
[2]