2014 Dec

Approved calculators and molecular models may be used.
1. A compound containing C, H, F and P has the following composition by

mass:
C, 9.8% ; H, 2.5% ; F, 62.3% ; P, 25.4%
Use these data to find the empirical formula of the compound.
[Atomic masses/ g mol-1 : C, 12.01 ; H, 1.01 ; F, 19.00 ; P, 30.97]
(2 marks)
2. Permanganate ion (MnO4-) reacts with arsenic trioxide (As4O6) in acid

solutions, to form the Mn2+ ion and AsO43-. Using the half-equation
method, write a balanced equation for this redox reaction.
(3 marks)
3. Rank the following Group 16 hydrides in order of increasing acid strength:

H2S H2O H2Te
Explain your answer.
(3 marks)
4. Sulfur tetrafluoride (SF4) shows the following chemistry:

• it reacts with BF3, producing the SF3+ cation
• it reacts with CsF, producing the SF5- anion.
(a) Draw structures for the sulfur containing product of each reaction.
(1 mark)
(b) Give the hybridization of the sulfur atom in each case.

(1 mark)
(c) What name is given to this type of reaction, and explain why SF 4
behaves differently in the two reactions?
(2 marks)
5. Ethanol (CH3-CH2-OH) and dimethyl ether (CH3-O-CH3) have the same
empirical formula (C2H6O). One of these compounds has a boiling
B17CA
point of 352K while the other has a boiling point of 250K. Predict which
of the two compounds has the higher boiling point and explain the
reason for the large difference between the two values.
Illustrate your answer with a diagram.
(2 marks)
6. Chlorine forms a family of oxy acids (HOCl, HOClO, HOClO2 and

HOClO3) but fluorine forms HOF as its only oxy acid. Draw structures
for these species and explain why chlorine and fluorine behave so
differently.
(3 marks)
7. The element titanium has atomic number 22.
(a) Write down, in full, the ground state electronic configuration

of titanium.
(0.5 marks)
(b) Draw the ground state energy level diagram for a titanium atom. Label
all atomic orbitals and include all electrons. How many unpaired
electrons, if any, does titanium have?
(2 marks)
(c) In which group and which period of the Periodic Table does titanium
sit? Is it a non-metal, a metalloid, a main group metal or a
transition metal?
(1.5 marks)
(d) Light with a wavelength of 105 nm is incident on titanium in a vacuum,

resulting in the ejection of electrons with a kinetic energy of
10.3×10–19 J. Calculate the work function for titanium.
[h = 6.626×10−34 J s; c = 2.998×108 m s−1]

(2 marks)
8. Three main group elements, X, Y and Z, from three different groups in
the Periodic Table, each form a neutral trifluoride, i.e. XF3, YF3 and
ZF3.
Page 2 of 5
B17CA
(a) To which three groups of the Periodic Table could the elements X, Y
and Z belong? Are any of these atoms X, Y or Z hypervalent in
the trifluorides formed?
(2 marks)
(b) Use VSEPR theory to deduce the shapes of the molecules XF3, YF3
and ZF3, showing full working, and sketch these shapes.
(3 marks)
(c) Only two of the three trifluorides have a non-zero dipole moment. For
these molecules to which groups of the Periodic Table do the
central atoms belong?
(1 mark)
9. (a) Explain why N has a higher Ei1 than both C and O.

` (0.5 marks)
(b) Explain why Ei3 for Ca is considerably greater than either Ei1 or
Ei2.
(0.5 marks)
(c) What is the hybridisation at the central atom in the following molecules
or ions? (you do not need to draw a valence bond construction)
(i) [I3]+
(ii) OF2
(iii) [ICl5F]+
(3 marks)
10. Draw the structures of the products for the following reactions. Draw
curly arrow mechanisms to describe each reaction.
Page 3 of 5
B17CA
(6 marks)
11. Complete a Newman projection (B) for compound A viewed from C1

towards C2. Is this a staggered or eclipsed conformation?
Ph H OH
View 2
along 1
C1-C2
bond
Cl H Me Cl
B
A
(3 marks)
12. Draw a curly arrow mechanism to clearly describe why the following
reaction gives a trans dibromo product.
(3 marks)
13. Draw the structures of the products for the following reactions. For (iii),
draw a curly arrow mechanism to explain your regioselectivity.
Page 4 of 5
B17CA
(i)
OH
CrO3
H2SO4, H2O
(ii)
O H2, Pd/C
(iii) HBr
(5 marks)
END OF PAPER
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2014 Dec

Uploaded by

Copyright:

Available Formats

Approved calculators and molecular models may be used.

1. A compound containing C, H, F and P has the following composition by

2. Permanganate ion (MnO4-) reacts with arsenic trioxide (As4O6) in acid

3. Rank the following Group 16 hydrides in order of increasing acid strength:

4. Sulfur tetrafluoride (SF4) shows the following chemistry:

(b) Give the hybridization of the sulfur atom in each case.

6. Chlorine forms a family of oxy acids (HOCl, HOClO, HOClO2 and

7. The element titanium has atomic number 22.

(a) Write down, in full, the ground state electronic configuration

(d) Light with a wavelength of 105 nm is incident on titanium in a vacuum,

[h = 6.626×10−34 J s; c = 2.998×108 m s−1]

9. (a) Explain why N has a higher Ei1 than both C and O.

11. Complete a Newman projection (B) for compound A viewed from C1

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