AS & A Level Chemistry - 9701 Paper 2 2014 Winter Zone 3

(a) Successive ionisation energies for the elements fluorine, F, to bromine, Br, are shown on the graph.

(i) Explain why the first ionisation energies decrease down the group.
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[3]
(ii) Explain why there is an increase in the successive ionisation energies of fluorine.
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[2]
(b) Group VII is the only group in the Periodic Table containing elements in all three states of matter at room conditions.
State and explain, in terms of intermolecular forces, the trend in the boiling points of the elements down Group VII.
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[4]

(c) Compounds containing different halogen atoms covalently bonded together are called interhalogen compounds.
(i) One interhalogen compound can be prepared by the reaction between iodine and fluorine. This compound has $M_r = 222$ and the percentage composition by mass: F, 42.8; I, 57.2.
Calculate the molecular formula of this interhalogen compound.
molecular formula: ....................................
[3]
(ii) Another interhalogen compound has the formula ICl.
Draw a ‘dot-and-cross’ diagram of a molecule of this compound, showing outer shell electrons only. Explain whether or not you would expect this molecule to be polar.
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[2]

(d) Some reactions involving chlorine and its compounds are shown in the reaction scheme below.

(i) Give the formulae of W, X, Y and Z.
W: ..............................................................
X: ..............................................................
Y: ..............................................................
Z: ..............................................................
[4]
(ii) Write an equation for the reaction of chlorine with hot NaOH(aq).
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[2]
(iii) State the oxidation numbers of chlorine at the start and at the end of the reaction in (ii).
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[2]
(iv) Write an ionic equation for the reaction of Y with AgNO$_3$(aq). Include state symbols.
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[1]

(a) The hydrogen for this reaction can be formed by reacting methane with steam, during which carbon monoxide is also produced. Write an equation for this reaction.
[1]

(b) Use the Boltzmann distribution shown to explain why a catalyst increases the rate of this reaction.

[4]

(c) Draw a three-dimensional diagram to show the shape of an ammonia molecule. Name this shape and state the bond angle.
shape ................................................ bond angle ......................................
[3]

(d) The Haber process is typically carried out at a temperature of 400°C.
(i) With reference to Le Chatelier’s Principle and reaction kinetics, state and explain one advantage and one disadvantage of using a higher temperature.
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[4]
(ii) State the expression for the equilibrium constant, $K_p$, for the formation of ammonia from nitrogen and hydrogen in the Haber process.
$K_p$ = ..........................
[1]
(iii) 2.00 moles of nitrogen and 3.00 moles of hydrogen were put in a vessel and left to reach equilibrium.
At equilibrium, the pressure was $2.00 \times 10^{7}$ Pa and the mixture contained 1.60 moles of ammonia.
Calculate $K_p$. Include the units.
$K_p$ = ..........................
units = ..........................
[5]

P, Q, R and S are structural isomers with the molecular formula $C_5H_{10}$.

All four compounds readily decolourise bromine in the dark.

P, R and S do not exhibit stereoisomerism but Q exists as a pair of geometrical (cis-trans) isomers.

All four compounds react with hot concentrated, acidified potassium manganate(VII) to produce a variety of products as shown in the table.

[Table_1]
compound | products
P | $CO_2$ and $CH_3CH_2CH_2CO_2H$
Q | $CH_3CO_2H$ and $CH_3CH_2CO_2H$
R | $CO_2$ and T ($C_4H_8O$)
S | $CH_3CO_2H$ and $(CH_3)_2CO$

T reacts with 2,4-dinitrophenylhydrazine reagent, 2,4-DNPH, to form an orange crystalline product but does not react with Fehling's reagent.

(a) Give the structural formulae of P, Q, R, S and T.

P ............................................................... Q ..............................................................
R ............................................................... S ..............................................................
T ................................................................................................................. [5]

(b) (i) Explain what is meant by the term stereoisomerism.

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..............................................................................................................................[2]

(ii) Draw the displayed formulae of the geometrical isomers of Q and name them both.

name .......................................................... name .......................................................... [2]

(c) Name the organic product of the reaction of T with sodium borohydride, $NaBH_4$.

.............................................................................................................................. [1]

A series of reactions based on propan-1-ol is shown.



(a) Suggest a suitable reagent and conditions for reaction 1.
....................................................................................................................... [2]

(b) (i) Write an equation for reaction 2, using [O] to represent the oxidising agent.
....................................................................................................................... [1]
(ii) Suggest a suitable reagent and conditions for reaction 2.
....................................................................................................................... [2]

(c) Give the structural formulae of U and V.
U .......................................................................................................................
V ....................................................................................................................... [2]

(d) Suggest a suitable reagent and conditions for reaction 3.
....................................................................................................................... [2]