11 mark
Hydrazine, N2H4, is a precursor for multiple pharmaceutical compounds.
Which of the diagrams below illustrate the most likely structure and bond angle of hydrazine?
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Syllabus Edition
First teaching 2014
Last exams 2024
|
Resonance, Shapes & Giant Structures (DP IB Chemistry: HL)
Exam Questions
3 hours43 questions21 mark
Two boron-containing species, boron trifluoride (BF3) and the borohydride ion (BH4-), have different molecular shapes.
What are the shapes around the boron atom in these molecules?
|
|
boron trifluoride (BF3) |
borohydride ion (BH4−) |
|
A |
pyramidal |
tetrahedral |
|
B |
pyramidal |
square planar |
|
C |
trigonal planar |
tetrahedral |
|
D |
trigonal planar |
square planar |
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31 mark
Graphite has a structure containing layers of carbon atoms in hexagonal rings.
Why is graphite a good conductor of electricity?
It has delocalised ions which can move and carry charge
It has delocalised electrons which are mobile
There are only weak London forces between the layers
Each carbon atom in the layers has only three covalent bonds
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41 mark
What is the correct bond angle in a trigonal planar molecule?
107°
120°
180°
109.5°
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51 mark
Which of the following is correct?
|
|
Shape of SF6 molecule |
Bond angle in SF6 molecule |
|
A |
Octahedral |
90° |
|
B |
Square planar |
90° |
|
C |
Trigonal bipyramidal |
120° |
|
D |
Tetrahedral |
109.5° |
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61 mark
Which statement about the physical properties of substances is correct?
Covalent structures always have high melting points
Metals only conduct electricity when solid
Metals always have high melting points
Ionic substances conduct electricity when liquid
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71 mark
Which of the following statements about graphite is correct?
The bond angle in graphite is 109.5 o
There are only London forces between the layers of graphite
Graphite has a higher melting point than diamond
Graphite is soluble in water
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81 mark
Which of the following is the correct resonance hybrid structure of the carbonate ion, CO32-?
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91 mark
Which of the following is correct?
|
|
Shape of CCl4 molecule |
Bond angle in CCl4 molecule |
|
A |
Octahedral |
90° |
|
B |
Square planar |
90° |
|
C |
Trigonal bipyramidal |
120° |
|
D |
Tetrahedral |
109.5° |
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101 mark
Which substance is described in the table below?
|
Melting point |
Electrical Conductivity |
Solubility |
|
Very high |
Non-conductor |
Does not dissolve |
Silicon dioxide
Buckminsterfullerene
Graphite
Sodium chloride
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11 mark
The following equation shows the dissociation equilibrium of PCl5.
PCl5(g) → PCl3(g) ＋ Cl2(g)
The percentage yield of PCl3 varies with temperature.
At 160°C PCl3 yield is 13% and at 300°C yield is100%.
Which of the following rows is correct?
|
|
The reaction is |
Shape of PCl3 molecule |
|
A |
exothermic |
trigonal pyramidal |
|
B |
exothermic |
trigonal planar |
|
C |
endothermic |
trigonal pyramidal |
|
D |
endothermic |
trigonal planar |
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21 mark
Boron trifluoride, BF3, reacts with trimethylamine, (CH3)3N, to form a compound of formula (CH3)3N.BF3.
How may this reaction be written using 3D structures to show the shapes of the reactants and products?
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31 mark
Which of the following statements about graphite are correct?
- The carbon atoms are joined together by three covalent bonds
- Graphite contains delocalised electrons
- The C-C-C bond angle is 109.5o
I and II only
I and III only
II and III only
I, II and III
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41 mark
Which statement below shows the correct information about diamond and silicon?
Diamond is macromolecular and silicon is simple molecular
The bond angles in the two structures are the same
The bond lengths are longer in C-C than in Si-Si
Diamond and silicon both conduct electricity due to delocalised electrons in their structure
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51 mark
How many lone pairs of electrons are there around the chlorine atom in a molecule of chlorine trifluoride, ClF3?
1
2
3
0
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61 mark
Which one of these species has a bond angle of 120°?
H3O+
TlBr32-
BCl3
NH3
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71 mark
Which of the following statements about silicon dioxide is correct?
- Silicon dioxide forms a giant covalent network
- Each silicon atom is covalently bonded to four oxygen atoms
- Silicon dioxide molecules are V-shaped
I and II only
I and III only
II and III only
I, II and III
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81 mark
Ibuprofen is an anti-inflammatory drug that is used for treating pain, fever and inflammation. The structure is shown below.
Ibuprofen
What are the correct bond angles for a and b?
|
|
a |
b |
|
A |
120o |
120o |
|
B |
107o |
109.5o |
|
C |
109.5o |
120o |
|
D |
120o |
109.5o |
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91 mark
Which of the following molecules obeys the octet rule?
BF3
HCN
BeCl2
CS2
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101 mark
Which row in the table is correct?
|
|
Shape of diamond structure |
Melting point of buckminsterfullerene |
Bond angle in graphene |
|
A |
Square planar |
Relatively high |
90o |
|
B |
Tetrahedral |
Relatively low |
107o |
|
C |
Trigonal Planar |
Relatively high |
109.5o |
|
D |
Tetrahedral |
Relatively low |
120o |
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11 mark
Which of the species shown below does not have resonance structures?
C6H6
CO32-
C2H4
O3
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21 mark
The correct molecular geometry and domain geometry for phosphorus trichloride, PCl3, is:
|
|
molecular geometry |
domain geometry |
|
A |
trigonal planar |
trigonal planar |
|
B |
trigonal pyramid |
tetrahedral |
|
C |
tetrahedral |
trigonal planar |
|
D |
tetrahedral |
trigonal pyramid |
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31 mark
Below are statements about the structure and bonding in silicon dioxide. Which pair of statements is correct?
|
|
structure |
bonding |
|
A |
silicon dioxide molecules are bent linear |
silicon atoms have covalent bonds to two oxygen atoms |
|
B |
silicon dioxide has a giant macromolecular structure |
each oxygen bonds covalently to one silicon atom |
|
C |
silicon dioxide has a giant macromolecular structure |
silicon atoms bond to four oxygen atoms |
|
D |
silicon dioxide molecules are linear |
silicon and oxygen atoms are joined by a double covalent bond |
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41 mark
Which compounds have an ionic lattice structure in the solid state?
- silicon dioxide
- sodium iodide
- ammonium sulfate
I and II only
I and III only
II and III only
I, II and III
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51 mark
What is the correct shape of a ClF2- ion?
Linear
T-Shaped
Bent
Trigonal planar
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61 mark
The correct shape and bond angle for the TlBr32- ion?
|
|
Shape |
Bond angle |
|
A |
Pyramidal |
120° |
|
B |
Pyramidal |
107° |
|
C |
Tetrahedral |
109.5° |
|
D |
Tetrahedral |
120° |
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71 mark
Which of the following is correct for the molecules of BeCl2 and BeCl42-?
|
BeCl2 |
BeCl42- |
|
Shape |
Bond angle |
Shape |
Bond angle |
|
|
A |
Linear |
109.5° |
Square planar |
90° |
|
B |
V-shaped |
107° |
Square planar |
90° |
|
C |
V-shaped |
105° |
Tetrahedral |
109.5° |
|
D |
Linear |
180° |
Tetrahedral |
109.5° |
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81 mark
Tramadol is an example of a painkiller which is classed as an opioid analgesic. It binds to opioid receptors in the central nervous system and inhibits noradrenaline and serotonin reuptake inhibiting pain transmission
The structure is shown below
Which of the following are the correct bond angles for a, b and c?
|
a |
b |
c |
|
|
A |
120o |
109.5o |
107o |
|
B |
120o |
107o |
105o |
|
C |
107o |
109.5o |
107o |
|
D |
109.5o |
107o |
105o |
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91 mark
Some properties of substance X are given in the following table
|
Melting Point |
Very high |
|
Strength |
Very strong across the layer |
|
Conductivity |
Excellent conductor |
|
Example of a Use |
Used as a coating for smartphones, tablets and computers |
What is a possible identity of substance X?
Graphene
Graphite
Silicon dioxide
Buckminsterfullerene
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101 mark
Sulfur forms the compound S4N4 with nitrogen, the structure is shown below.
Which of the following statements about S4N4 is correct?
The sulfur atom marked x has two lone pairs
The sulfur atom marked y has two lone pairs
Each N atom has two lone pairs
The N-S-N bond angle will be larger than S=N=S bond angle
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