8
2I–(aq) + S O2–(aq) (cid:114) I (aq) + 2SO2–(aq)
Question
Mathematics
Edexcel2017
8 2 4
This reaction is catalysed by iron(II) ions, Fe2+(aq).
Write two ionic equations to show how iron(II) ions act as a catalyst in this reaction.
State symbols are not required.
(2)
(Total for Question 4 = 9 marks)
Question
Mathematics
Edexcel2017
3
C 2Al(s) + 1½ O (g) (cid:114) Al O (s)
Question
Mathematics
Edexcel2017
2 3
D 2Al(s) + 3 O(g) (cid:114) Al O (s)
Question
Mathematics
Edexcel2017
3
(b) Propan-1-ol is dehydrated to form propene.
H H
H H H
C C
H C C C O H + H O (cid:168) H = +42 kJ mol−1
Question
Mathematics
Edexcel2017
r
H C H
H H H
H H
The relevant mean bond enthalpies are given in the table.
Mean bond enthalpy
Bond
/ kJ mol–1
C C 347
C C 612
C H 413
O H 464
Calculate the C O mean bond enthalpy, using the mean bond enthalpies given
in the table and the enthalpy change of reaction.
(3)
Question
Mathematics
Edexcel2017
B 2H O (l) (cid:114) 2H O(l) + O (g) 2 2 2 2
C MgCO (s) + H SO (aq) (cid:114) MgSO (aq) + H O(l) + CO (g)
Question
Mathematics
Edexcel2017
2
(d) What is the expression for (cid:168)S ?
total
(1)
(cid:168)H
A (cid:168)S + –
surroundings T
(cid:168)H
B (cid:168)S – –
surroundings T
(cid:168)H
C (cid:168)S + –
system T
(cid:168)H
D (cid:168)S – –
system T
Question
Mathematics
Edexcel2017
(a) (i) Draw a dot-and-cross diagram to show the bonding in magnesium bromide.
Only outer shell electrons are required.
(1)
(ii) State all the conditions under which magnesium bromide conducts electricity.
(1)
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Question
Mathematics
Edexcel2017
enthalpy change of formation of magnesium bromide, (cid:168)H [MgBr (s)] –524
f 2
(i) Complete the Born-Haber cycle for magnesium bromide with formulae,
electrons and labelled arrows. The cycle is not drawn to scale.
(3)
Mg(g) + Br (l)
Question
Mathematics
Edexcel2017
(cid:168) H [Mg(s)]
at
Mg(s) + Br (l)
Question
Mathematics
Edexcel2017
(cid:168)H [MgBr (s)]
f 2
MgBr (s)
Question
Mathematics
Edexcel2017
–
– – – – – – – – –
pH
Question
Mathematics
Edexcel2017
4
ethanoic acid, CH COOH –56
Question
Mathematics
Edexcel2017
used in some skincare products.
It has a K value of 1.5 × 10–4 mol dm–3.
a
The structure of glycolic acid is
H
O
H C C
OH
OH
(a) A solution of glycolic acid of concentration 0.1 mol dm–3 has a pH of 2.4
What is the approximate pH of the resulting solution after it has been diluted by a
factor of 100?
(1)
A 1.4
B 2.4
C 3.4
D 4.4
(b) Another solution of glycolic acid has a pH of 2.0
Calculate the concentration of this solution.
(3)
Question
Mathematics
Edexcel2017
3 .............................................................. ..............................................................
(Total for Question 8 = 12 marks)
Turn over
Question
Mathematics
Edexcel2017
4
Write the ionic equations involving HPO2– and H PO– ions to show how this
Question
Mathematics
Edexcel2017
K = —
p
p(H O)
Question
Mathematics
Edexcel2017
(i) Give a reason why the partial pressure of carbon is not included in the expression.
(1)
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(ii) Explain the effect of an increase in pressure on the equilibrium position of this reaction.
(2)
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(iii) Explain, by reference to any change in the value of K , the effect of an increase
p
in temperature on the equilibrium position of this reaction.
(2)
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Question
Mathematics
Edexcel2017
2 2
At 1100 K, K = 1.00
c
In an experiment, 1 mol of carbon monoxide was mixed with 1 mol of steam,
Question
Mathematics
Edexcel2017
mol of carbon dioxide and 2 mol of hydrogen.
Deduce, with reasons, the direction in which the reaction will shift to reach equilibrium.
(3)
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(Total for Question 10 = 12 marks)
TOTAL FOR PAPER = 90 MARKS
Question
Mathematics
Edexcel2017
2
The expression for the equilibrium constant, K , is
p
p(H ) p(CO)
*P48058A0228*
DO
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Answer ALL questions.
Some questions must be answered with a cross in a box .
If you change your mind about an answer, put a line through the box
and then mark your new answer with a cross .
Question
Mathematics
Edexcel2017
Magnesium nitrate decomposes on heating as shown by the equation.
2Mg(NO ) (cid:114) 2MgO + 4NO + O
D Mn 2+(aq)
(ii) Write the ionic equation and calculate the E value for the reaction between
cell
MnO– ions and Br – ions in acidic solution.
Question
Mathematics
Edexcel2017
6 2 6
form a colourless solution.
Explain why zinc ions are colourless.
(2)
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(c) Hydrated iron(II) ions react with ethanedioate ions, C O2–, to form a complex ion.
Question
Mathematics
Edexcel2017
4
[Fe(H O) ]2+ + 2C O2– (cid:85) [Fe(C O ) (H O) ]2– + 4H O
Question
Mathematics
Edexcel2017
6 2 4 2 4 2 2 2 2
(i) Draw a structure of the [Fe(C O ) (H O) ]2– ion, showing all of the bonds.