SL Bonding 2
1.
What is the formula of an ionic compound formed by element X (group 2) and element Y
(group 6)?
A.
X3Y
B.
X2Y
C.
XY2
D.
XY
(1)
2.
Based on electronegativity values, which bond is the most polar?
A.
B–C
B.
C–O
C.
N–O
D.
O–F
(1)
3.
What is the Lewis (electron dot) structure for sulfur dioxide?
A.
O S O
B.
O S O
C.
O
S
D.
O
S O
O
(1)
4.
Which substance is most soluble in water (in mol dm−3) at 298 K?
A.
CH3CH3
B.
CH3OCH3
C.
CH3CH2OH
D.
CH3CH2CH2CH2OH
(1)
1
5.
(i)
Draw Lewis (electron dot) structures for CO2 and H2S showing all valence electrons.
(2)
(ii)
State the shape of each molecule and explain your answer in terms of VSEPR theory.
CO2 .............................................................................................................................
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H2S .............................................................................................................................
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(4)
(iii)
State and explain whether each molecule is polar or non-polar.
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(2)
(Total 8 marks)
6.
Identify the strongest type of intermolecular force in each of the following compounds.
CH3Cl ...................................................................................................................................
CH4 .......................................................................................................................................
CH3OH .................................................................................................................................
(Total 3 marks)
7.
Which of the following species is (are) planar (has (have) all the atoms in one plane)?
2–
3
I.
CO
II.
NO 3–
III.
SO
2–
3
A.
I only
B.
II only
C.
I and II only
D.
II and III only
(1)
2
8.
Draw Lewis (electron dot) structures for the following ions.
NO2–
NO2+
Determine and explain the shape of each ion.
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(Total 6 marks)
9.
(i)
List the following substances in order of increasing boiling point (lowest first).
CH3CHO
C2H6
CH3COOH
C2H5OH
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(2)
(ii)
State whether each compound is polar or non-polar, and explain the order of boiling
points in (c)(i).
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(8)
(Total 10 marks)
3
10.
According to VSEPR theory, repulsion between electron pairs in a valence shell decreases in
the order
A.
lone pair-lone pair > lone pair-bond pair > bond pair-bond pair.
B.
bond pair-bond pair > lone pair-bond pair > lone pair-lone pair.
C.
lone pair-lone pair > bond pair-bond pair > bond pair-lone pair.
D.
bond pair-bond pair > lone pair-lone pair > lone pair-bond pair.
(1)
11.
Which molecule is linear?
A.
SO2
B.
CO2
C.
H2S
D.
Cl2O
(1)
12.
Why is the boiling point of PH3 lower than that of NH3?
A.
PH3 is non-polar whereas NH3 is polar.
B.
PH3 is not hydrogen bonded whereas NH3 is hydrogen bonded.
C.
Van der Waals’ forces are weaker in PH3 than in NH3
D.
The molar mass of PH3 is greater than that of NH3
(1)
13.
Which molecule is non-polar?
A.
H2CO
B.
SO3
C.
NF3
D.
CHCl3
(1)
14.
(a)
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.
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(2)
4
(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
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(3)
(iii)
State the H–N–H bond angle in an ammonia molecule.
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(1)
(iv)
Explain why the ammonia molecule is polar.
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(1)
(b)
Ammonia reacts with hydrogen ions forming ammonium ions, NH4+.
(i)
State the H–N–H bond angle in an ammonium ion.
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(1)
(ii)
Explain why the H–N–H bond angle of NH3 is different from the H–N–H bond
angle of NH 4 ; referring to both species in your answer.
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(3)
(Total 11 marks)
5
15.
In 1954 Linus Pauling was awarded the Chemistry Nobel Prize for his work on the nature of the
chemical bond. Covalent bonds are one example of intramolecular bonding.
Explain the formation of the following.
(i)
σ bonding
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(2)
(ii)
π bonding
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(2)
(iii)
double bonds
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(1)
(iv)
triple bonds
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(1)
(Total 6 marks)
16.
Atomic orbitals can mix by hybridization to form new orbitals for bonding.
Identify the type of hybridization present in each of the three following molecules.
Deduce and explain their shapes.
(i)
OF2
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6
(3)
(ii)
H2CO
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(3)
(iii)
C2H2
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(3)
(Total 9 marks)
17.
Three scientists shared the Chemistry Nobel Prize in 1996 for the discovery of fullerenes.
Fullerenes, like diamond and graphite, are allotropes of the element carbon.
(i)
State the structures of and the bonding in diamond and graphite.
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(2)
(ii)
Compare and explain the hardness and electrical conductivity of diamond and graphite.
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(4)
7
(iii)
Predict and explain how the hardness and electrical conductivity of C60 fullerene would
compare with that of diamond and graphite.
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(4)
(Total 10 marks)
8