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SECTION A: Short questions (25 Marks)
1 point
1
Question 1
1.
Which of the following compounds has the lowest boiling point?
1 point
1
Question 2
2.
Which of the following contain polar covalent bonds, but experience no net dipole?
6 points
6
Question 3
3.
Identify the best explanation for differences in boiling points in each set of examples, by dragging them to appropriate explanation.
noble gases
butan-2-ol and butane-1,2-diol
hexane and methane
2-bromopentane and 2-bromo-2-methylbutane
halogens
NH3 and PH3
Differences in intermolecular forces strength
Differences in electron number and therefore the strength of the temporary dipole
Differences in opportunities for London forces
Differences in number of hydrogen bonds formed
1 point
1
Question 4
4.
Which answer correctly arranges these compounds in order of DECREASING boiling point?
1 point
1
Question 5
5.
Which substance has the lowest boiling point?
1 point
1
Question 6
6.
Which option correctly arranges the substances in order of INCREASING boiling point?
1 point
1
Question 7
7.
Consider substances X, Y and Z, which all have a molar mass of 60 g.mol-1:
Which one of the following is the most likely boiling point of Y?
8 points
8
Question 8
8.
Match the following substances with the statement that best describes it.
Draggable item
arrow_right_alt
Corresponding Item
ammonia
arrow_right_alt
A substance with a giant network structure in which the atoms are held together by covalent bonds
hydrogen bromide
arrow_right_alt
A substance with hydrogen bonding forces
carbon dioxide
arrow_right_alt
A substance with a high melting point due to strong electrostatic attraction between cations and anions in the crystal lattice.
graphite
arrow_right_alt
A substance which has London forces between atoms in liquid or solid state
helium
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A molecular substance with non-polar covalent bonds
bromine
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A molecular substance which has dipole-dipole intermolecular forces
barium oxide
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A substance that can conduct electricity in both the solid and liquid phase
sodium
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A linear molecular substance with polar covalent bonds
1 point
1
Question 9
9.
A molecule of hexane is considered to be non-polar. Which one of the statements best describes the reason why the molecule is non-polar?
1 point
1
Question 10
10.
The table below lists three properties of solids.
Which one of the solids (A-D) has its particular properties listed correctly?
1 point
1
Question 11
11.
A scientist investigates a factor that influences the boiling points of alkanes. He determines the boiling points of the first six straight chain alkanes. Which one of these is the independent variable in this investigation?
1 point
1
Question 12
12.
Which of these hypothetical substances will be a liquid at room temperature?
1 point
1
Question 13
13.
Which of the following exists as a solid in a molecular crystal lattice with dipole-dipole forces between particles/subunits?
Section B: Longer Questions (25 Marks)
Question 1 (9 marks)
Surface tension can be used as an indication of the strength of the intermolecular forces in a substance. Watch the video illustrating an experiment to determine which substance (A, B or C) has the strongest intermolecular forces, and answer the questions that follow:
If you are unable to view the video: copy this link and watch it in separate window: https://drive.google.com/open?id=1Q-wqRmwSCm6v1DILa2huP7dTN58RvCFR
1 point
1
Question 14
14.
1.1 What is the independent variable in this experiment? [Link for video https://drive.google.com/open?id=1PwV0P8vsYTWPz-eOt_ZjDE44_EJDH0xK]
1 point
1
Question 15
15.
1.2 What is the dependent variable in this experiment?
3 points
3
Question 16
16.
1.3 Complete the table of results for the experiment shown in the video (using the text tool instead of the pen tool may be easier, the size of the text is adjusted using the pen thickness button):
3 points
3
Question 17
17.
1.4 Match each of these substances to the IMF that is most likely present based on these results.
Draggable item
arrow_right_alt
Corresponding Item
C
arrow_right_alt
hydrogen bonding
A
arrow_right_alt
London forces
B
arrow_right_alt
dipole-dipole forces
1 point
1
Question 18
18.
1.5 Suggest ONE controlled variable for this experiment.
Question 2 (16 marks)
Consider the boiling points of the substances in the table and answer the questions that follow:
1 point
1
Question 19
19.
2.1 The boiling point of methane is greater than that of oxygen because ....
6 points
6
Question 20
20.
2.3 Draw TWO hydrogen sulphide molecules, indicating and labelling the following:
- the elements
- the partial charges
- intramolecular forces (name them)
- intermolecular forces (name them)
(Consider using the circle shape to represent atoms, remember you have an eraser too )
4 points
4
Question 21
21.
2.4 Why is the hydrogen sulphide molecule 'bent" in shape?
1 point
1
Question 22
22.
2.5 What determines bond polarity?
4 points
4
Question 23
23.
2.6 Carbon monoxide and hydrogen fluoride have vastly different boiling points. Use your knowledge of intermolecular forces to explain why their boiling points differ so greatly. Type each point on a new line!
THE END OF THE ASSESSMENT. CHECK YOUR ANSWERS, SUBMIT AND GO GRAB A HOT CHOCOLATE !