Chemistry 11 (HL)
April 2013
Mini Practice Exam A
PAPER 1: Do not use a calculator or the Data Booklet. Allow 23 minutes.
1.
Ethyne, C2H2, reacts with oxygen according to the equation below. What volume of oxygen
3
3
(in dm ) reacts with 0.40 dm of C2H2?
2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g)
A.
0.40
B.
0.80
C.
1.0
D.
2.0
2.
Which solution contains the smallest amount of nitrate (NO3 ions)?
3
–3
3
–3
A.
10.0 cm of 0.250 mol dm NaNO3
B. 20.0 cm of 0.250 mol dm NaNO3
3
–3
3
–3
C.
10.0 cm of 0.500 mol dm NaNO3
D. 10.0 cm of 0.250 mol dm Ca(NO3)2
3.
What is the difference between two neutral atoms represented by the symbols
and 210At?
A.
The number of neutrons only.
B.
The number of protons and electrons only.
C.
The number of protons and neutrons only.
D.
The number of protons, neutrons and electrons.
4.
How many electrons are there in all the d orbitals in an atom of xenon?
A.
10
B.
18
C.
20
D.
36
5.
Rubidium is an element in the same group of the periodic table as lithium and sodium.
It is likely to be a metal which has a
A.
high melting point and reacts slowly with water.
B.
high melting point and reacts vigorously with water.
C.
low melting point and reacts vigorously with water.
D.
low melting point and reacts slowly with water.
6.
Which of these molecules has atoms with sp hybridization?
A.
C 2H 6
B.
CO2
C. C6H6
D. C4H6
7.
What is the best description of the carbon-oxygen bond lengths in CO3
A.
One short and two long bonds
B.
One long and two short bonds
C.
Three bonds of the same length
D.
Three bonds of different lengths
8.
The compounds listed have very similar molar masses. Which has the strongest intermolecular
forces?
A.
CH3CHO
B.
CH3CH2OH
C.
CH3CH2F
D.
CH3CH2CH3
2–
210
Po
?
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Chemistry 11 (HL)
9.
April 2013
How many hydrogen atoms are in 0.500 mol of CH3OH molecules?
23
23
A. 1.20 x 10
23
C. 6.02 x 10
10.
B. 3.01 x 10
24
D. 1.20 x 10
5
A fixed mass of an ideal gas 1.01 x 10 Pa and at a temperature of 27.0˚C has a volume of 100
3
cm . What doubles the volume of the gas?
A.
B.
C.
D.
Heating the gas at constant pressure to 54.0ºC.
Heating the gas at constant pressure to 327ºC.
5
Increasing the pressure on the gas to 2.02 x 10 Pa while keeping constant temperature.
5
Heating the gas to 54.0ºC and increasing the pressure to 2.02 x 10 Pa.
11.
Which statement about bond enthalpies is correct?
A.
Bond enthalpies have positive values for strong bonds and negative values for weak
bonds.
B.
Bond enthalpy values are greater for ionic bonds than for covalent bonds.
C.
Bond breaking is endothermic and bond making is exothermic.
D.
The carbon–carbon bond enthalpy values are the same in ethane and ethene.
12.
Using the equations below:
C(s) + O2(g) → CO2(g)
Mn(s) + O2(g) → MnO2(s)
∆H = –390 kJ
∆H = –520 kJ
what is ∆H (in kJ) for the following reaction?
MnO2(s) + C(s) → Mn(s) + CO2(g)
A.
13.
910
B.
130
Given the equation:
C.
–130
D.
2CO(g)  2C(s) + O2(g)
–910
∆Hº = 220 kJ
Deduce the standard enthalpy of formation of carbon monoxide, CO.
14.
15.
A.
220 kJ mol
–1
B.
-220 kJ mol
–1
C.
110 kJ mol
–1
D.
-110 kJ mol
–1
–
+
Which of the following lists the species F , Na , Ne and F in order of increasing radius?
+
–
A.
Na < Ne < F < F
C.
Na < Ne < F < F
+
–
–
B.
F < F < Ne < Na
D.
F < F < Ne < Na
–
+
+
Which substance has the lowest melting point?
A.
SO3
B.
Cl2O
C.
Na2O
D.
MgO
p.2
Chemistry 11 (HL)
April 2013
PAPER 2: Calculators and the Data Booklet may be used. Allow 60 minutes only.
13.
A toxic gas, A, consists of 53.8% nitrogen and 46.2% carbon by mass.
a)
Deduce the empirical formula of the compound A. (2)
b)
5
3
At 273 K and 1.01×10 Pa, 1.048 g of A occupies 462 cm .
i) Determine the molar mass of the compound. (1)
ii) Determine the molecular formula of the compound. (1)
c)
Deduce the Lewis structure of compound A and predict its shape. (2)
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Chemistry 11 (HL)
14.
15.
April 2013
a)
Evidence for the existence of energy levels in atoms is provided by line spectra.
State how a line spectrum differs from a continuous spectrum. (1)
b)
On the diagram below draw four lines in the visible line spectrum of hydrogen. (1)
c)
Explain how the formation of lines indicates the presence of energy levels. (1)
Explain, with reference to atomic structure, why sulfur has a:
i)
lower first ionization energy than oxygen
ii)
lower first ionization energy than phosphorus.
(2 marks)
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Chemistry 11 (HL)
16.
a)
b)
April 2013
An important compound of nitrogen is ammonia, NH3. The chemistry of ammonia is
influenced by its polarity and its ability to form hydrogen bonds. Polarity can be explained
in terms of electronegativity.
(i)
Explain the term electronegativity. (2 mark)
(ii)
Draw a diagram to show hydrogen bonding between two molecules of NH3.
The diagram should include any dipoles and/or lone pairs of electrons (3 mark)
(iii)
State the H–N–H bond angle in an ammonia molecule. (1 mark)
(iv)
Explain why the ammonia molecule is polar. (1 mark)
+
Ammonia reacts with hydrogen ions forming ammonium ions, NH4 .
(i)
Identify the type of bond that forms when the hydrogen ion bonds to the ammonia
molecule. (1 mark)
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Chemistry 11 (HL)
17.
April 2013
(ii)
State the H–N–H bond angle in an ammonium ion. (1 mark)
(iii)
Explain why the H–N–H bond angle of NH3 is different from the H–N–H bond angle
+
of NH4 ; referring to both species in your answer. (3 marks)
An experiment was carried out to determine the enthalpy change of this reaction:
Mg(s) + CuSO4(aq)  Cu(s) + MgSO4(aq)
3
-3
50.0 cm of 0.500 mol dm CuSO4(aq) were transferred to a polystyrene cup with negligible heat
capacity, and the temperatures was recorded as 22.5ºC.
1.00 g of magnesium powder to added to the cup. The mixture was stirred and the highest
temperature reached was recorded as 85.6ºC.
a)
Show, by calculation, that CuSO4 is the limiting reactant. (2 marks)
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Chemistry 11 (HL)
b)
April 2013
i)
Calculate the heat change of the reaction mixture. (2 marks)
ii)
State one assumption you made when answering (i). (1 mark)
c)
Determine the enthalpy change for the reaction. (1 mark)
d)
Sketch an enthalpy diagram for this reaction. (2 marks)
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Chemistry 11 (HL)
18.
April 2013
There are many ways to represent a Born Haber cycle. The diagram below shows one possible
Born-Haber cycle for magnesium chloride, MgCl2:
a)
Define lattice enthalpy. (1 mark)
b)
Identify these quantities:
(2 marks)
II
III
continues on the next page
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Chemistry 11 (HL)
c)
19.
April 2013
Calculate the lattice enthalpy for magnesium chloride. (2 marks)
Given the following data:
a)
–1
C(s) + 2F2(g) → CF4(g)
∆H1 = –680 kJ mol
F2(g) → 2F(g)
∆H2 = +158 kJ mol
C(s) → C(g)
∆H3 = +715 kJ mol
–1
–1
Define average bond enthalpy. (1 mark)
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Chemistry 11 (HL)
b)
Calculate the average bond enthalpy (in kJ mol
April 2013
–1
) for the C–F bond. (3 marks)
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