1.	(a)	Draw the shape of each of the following molecules and mark on the diagram a value for the bond angle in each case.
(i)	CH4

(2)
 
(ii)	NH3

(2)
 
(iii)	BeCl2

(2)

(b)	Name the strongest type of intermolecular force present in separate samples of each of the following substances:
(i)	CH4
..........................................................................................................................
(1)
(ii)	HF
..........................................................................................................................
(1)
 
(c)	State and explain which of the substances CH4 and HF has the higher boiling temperature.
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(2)
(Total 10 marks)

2.	This question is about nitrogen trifluoride, NF3, and nitrogen trichloride, NCl3, which are covalent compounds. Van der Waals attractions and permanent dipole–dipole attractions exist between molecules of both compounds in the liquid state.
(a)	(i)	Describe how van der Waals attractions are caused.
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(1)
 
(ii)	In which of the two compounds would you expect there to be greater van der Waals attractions? Justify your answer.
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(1)
 
(iii)	In which of the two compounds would you expect there to be the greater permanent dipole–dipole attractions? Justify your answer.
............................................................................................................................
............................................................................................................................
 (1)
 
(iv)	The boiling point of nitrogen trichloride is much higher than that of nitrogen trifluoride. How might this be explained in terms of the two types of intermolecular attractions?
............................................................................................................................
............................................................................................................................
(1)
 
(b)	The standard enthalpy change for the formation of gaseous nitrogen trifluoride is
–125 kJ mol–1.
N2 (g)  +  1F2 (g)  ®  NF3 (g)  DHοf = –125 kJ mol–1
	The standard molar enthalpy changes of atomisation of nitrogen, N2, and of fluorine, F2, are given below.
	ΔHat/kJ mol–1
N2 (g) ® N (g)	+ 473
F2 (g) ® F (g)	  + 79

	This information can be represented on a Hess cycle in the following way, and then used to calculate bond energies.

(i)	Insert formulae, showing the correct quantities of each element, into the appropriate boxes.
(1)
(ii)	Insert arrows between the boxes and write the correct numerical data alongside the appropriate arrows.
(2)
 
(iii)	Use the cycle to calculate the N ¾ F bond energy in nitrogen trifluoride.

(2)
(Total 9 marks)

3.	(a)	State and explain the trend in the boiling temperatures of the noble gases. 
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(3)
 
(b)	The graph below shows the melting temperatures of the elements of Period 3 of the Periodic Table, sodium to argon, plotted against atomic number.

(i)	Identify one of the elements above that is composed of simple molecules at room temperature.
......................................................................................................................
(1)

(ii)	Silicon has a giant atomic structure. Explain how this structure results in the high melting temperature shown on the graph.
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(2)
 
(iii)	Explain why the melting temperature of magnesium is higher than that of sodium.
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(3)
(Total 9 marks)

4.	(a)	State the shape of a water molecule and explain why it has this shape.
Shape .....................................................................................................................
Explanation ............................................................................................................
...............................................................................................................................
...............................................................................................................................
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(3)

(b)	Predict the shape of the H3O+ ion and draw a diagram to illustrate its shape.
Shape ....................................................................................................................
Diagram

(2)
 
(c)	(i)	Use water as an example to explain what is meant by the term hydrogen bond.
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(3)

(ii)	State the difference in density between solid ice and liquid water and describe how the presence of hydrogen bonds accounts for this.
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(3)
(Total 11 marks)

5.	(a)	Complete the electronic configurations of the following noble gases.
(i)	Neon: 1s2 ....................................................................................................................
(1)
(ii)	Krypton: 1s2 ................................................................................................................
(1)
 
(b)	Explain whether krypton or neon has the higher boiling temperature.
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...............................................................................................................................................
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(2)

(c)	A mass spectrometer can be used to analyse a sample of a certain element.
	Explain how each of the following is achieved in a mass spectrometer.
(i)	Ionisation: ...................................................................................................................
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.....................................................................................................................................
(2)
(ii)	Acceleration: ..............................................................................................................
.....................................................................................................................................
(1)
(iii)	Deflection: ..................................................................................................................
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(1)
(Total 8 marks)

6.	This question is about the compounds of Group 6 elements with hydrogen.
	The table below shows some of the boiling points and molar masses of these hydrides.
Hydride	Boiling point /K	Mass of 1 mole /g	
Water, H2O	––	18	
Hydrogen sulphide, H2S	212	34	
Hydrogen selenide, H2Se	232	––	
Hydrogen telluride, H2Te	271	130	
 
(a)	What is the mass of one mole of hydrogen selenide, H2Se?
Use the Periodic Table as a source of data.

(1)

(b)	(i)	Plot a graph of the boiling points of the three hydrides H2S, H2Se, and H2Te against their molar masses.

(2)

(ii)	Why do the boiling points of these hydrides increase as the molar mass increases?
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(2)
 
(c)	(i)	Use your graph to predict the boiling point of water if it were to follow the pattern of the other three hydrides.
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(1)
(ii)	What causes the boiling point of water to be 373 K, rather than your answer in (i)?
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(1)
 
(iii)	Explain why this arises in water and not in the other hydrides.
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(1)
(iv)	Give the names of TWO other hydrides which, like water, have boiling points higher than you would expect.
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(2)

(d)	Give TWO properties of water, other than high melting and boiling points, which are brought about by the strong intermolecular forces between water molecules.
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(2)
(Total 12 marks)

7.	This question is about phosphine, PH3, and ammonia, NH3.
(a)	Which compound has the stronger van der Waals forces?
	Justify your answer.
.....................................................................................................................................
.....................................................................................................................................
(1)
 
(b)	(i)	The boiling points of ammonia and phosphine are:
	Ammonia	240 K
Phosphine	185 K 
	Name the intermolecular force responsible for the higher boiling point of ammonia.
...........................................................................................................................
(1)

(ii)	Use displayed formulae to show this intermolecular bond between two ammonia molecules.
	Clearly mark and label the bond angle between the molecules.

(2)
(Total 4 marks)

8.	You may find the following table useful in answering the question below.
Element	Electronegativity	
Hydrogen	2.1	
Oxygen	3.5	
	Draw a diagram to show a hydrogen bond between two water molecules and explain why it forms.
Diagram

Explanation ..........................................................................................................................
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(Total 4 marks)

9.	The table below shows some data for four organic compounds.
	Butane	Propan-1-ol	Propan-2-ol	Propanone	
Structural
formula	CH3CH2CH2CH3	CH3CH2CH2OH	CH3CH(OH)CH3	CH3COCH3	
Number of
electrons per
molecule	34	34	34	32	
Boiling
point/°C	–0.5	97.2	82.4	?	
 
(a)	The molecules of each compound contain a similar number of electrons. 
What type of intermolecular forces are likely to be similar in strength?
......................................................................................................................................
(1)
 
(b)	Explain why propan-1-ol boils at a higher temperature than
(i)	butane
...............................................................................................................................
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(1)
 
(ii)	propan-2-ol.
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(2)
(Total 4 marks)

10.	(a)	The table below gives the boiling points of three organic compounds.
Compound	Boiling point
/K	
chloroethane	285	
1-chloropropane	320	
2-chloropropane	309	
 
(i)	Explain why 1-chloropropane has a higher boiling point than chloroethane.
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(2)
 
(ii)	Explain why 1-chloropropane has a higher boiling point than its isomer, 2-chloropropane.
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(1)
 
(b)	Both chloroethane and iodoethane react with aqueous potassium hydroxide solution to form ethanol. The hydroxide ions act as nucleophiles.
(i)	What is a nucleophile?
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(1)

(ii)	Explain why iodoethane reacts faster than chloroethane with aqueous potassium hydroxide, under the same conditions.
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(1)
 
(c)	(i)	Under what conditions does chloroethane react with potassium hydroxide to form ethene rather than ethanol?
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(1)
 
(ii)	Name the type of reaction in which ethene is formed from chloroethane.
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(1)
(Total 7 marks)

11.	(a)	Draw the ammonia molecule, NH3, making its three-dimensional shape clear. Mark in the bond angle on your diagram. Explain why ammonia has this shape and this bond angle.
	Diagram

	Explanation
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(4)
 
(b)	Explain whether ammonia is a polar molecule or not.
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(2)

(c)	Explain, in terms of the intermolecular forces in both compounds, why ammonia has a higher boiling temperature than phosphine, PH3.
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(3)
 
(d)	(i)	Explain, in terms of electrons, how ammonia can react with hydrogen ions to form ammonium ions, NH4+.
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(2)
 
(ii)	State the number of protons and the number of electrons present in an ammonium ion.
	number of protons .....................................
	number of electrons....................................
(2)
(Total 13 marks)

12.	(a)	Methane and poly(ethene) are both hydrocarbons.
(i)	State the type of bond between carbon and hydrogen atoms in the molecules of both compounds.
.....................................................................................
(1)
 
(ii)	State the type of intermolecular force present in both compounds.
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(1)
 
(iii)	Explain why poly(ethene) melts at a higher temperature than methane.
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(3)
 
(b)	Explain, in terms of its bonding, why magnesium has a high melting temperature.
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(2)
(Total 7 marks)

13.	(a)	(i)	Explain why a water molecule does not have a linear shape.
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(2)
 
(ii)	State the HOH bond angle in water and explain why it has this value.
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(2)
 
(b)	(i)	Draw the boron trichloride molecule, BCl3, making its shape clear. Mark in the bond angle on your diagram.

(2)
 
(ii)	Explain why a B–Cl bond is polar.
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(1)
 
(iii)	Explain why a BCl3 molecule is non-polar.
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(1)
 
(iv)	Name the strongest intermolecular force between boron trichloride molecules.
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(1)
 
(c)	A compound of phosphorus and chlorine has the composition by mass shown below.
Element	% by mass	
P	14.9	
Cl	85.1	
	Calculate the empirical formula of this compound.

(2)
(Total 11 marks)

14.	Two reactions of a chloroalkane, X, are shown below.
Propanol-2-ol  Chloroalkane X  CH2=CHCH3
propene

(a)	The chloroalkane X can be used to make propan-2-ol in Reaction 1.
(i)	Name and draw the displayed formula of the chloroalkane X.
Name ...........................................................................................................
	Displayed formula

(2)
 
(ii)	Reaction 1 is an example of nucleophilic substitution. The nucleophile is the hydroxide ion. Use the diagram below to show how it is able to attack the chloroalkane X.

(2)
 
(b)	(i)	What type of reaction is Reaction 2?
.............................................................................
(1)

(ii)	Give the reagent and conditions needed for this reaction.
Reagent .............................................................................................................
Conditions .........................................................................................................
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(2)
 
(c)	Propan-2-ol has a higher boiling point than both the chloroalkane X and propene.
(i)	Name the strongest intermolecular force between propan-2-ol molecules.
...........................................................................
(1)
 
(ii)	Draw a diagram to show this force between two propan-2-ol molecules. Clearly mark and label the bond angle between the molecules.

(2)

(d)	Propene, CH2=CHCH3, can be polymerised forming poly(propene).
(i)	Draw a section of the poly(propene) polymer chain formed from two monomer units.

(2)
 
(ii)	Explain, in terms of intermolecular forces, why poly(propene) is a solid at room temperature.
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(2)
(Total 14 marks)

15.	(a)	The molecule isoprene has the displayed formula

(i)	Give the systematic name of isoprene.
...........................................................................................................................
(2)
 
(ii)	What colour change occurs when aqueous bromine solution is added to isoprene?
From ..................................................... to .......................................................
(1)
 
(iii)	State the type and mechanism of this reaction.
Type ................................................ Mechanism .............................................
(2)
 
(iv)	Suggest the displayed formula of the product formed when excess bromine reacts with isoprene in the dark.

(1)
 
(b)	Compound Q, an isomer of isoprene, has the structural formula
CH2 =CHCH2CH=CH2.
(i)	Give the name of the intermolecular force present in both isomers.
...........................................................................................................................
(1)

(ii)	Which isomer would you expect to have the higher boiling point? Justify your answer.
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(2)
(Total 9 marks)

16.	The graph shows the boiling temperatures of the hydrogen halides, hydrogen fluoride, HF, to hydrogen iodide, HI.

(a)	Complete the table to identify the strongest intermolecular forces present in the liquid form of each hydrogen halide.
Hydrogen
halide	Strongest intermolecular force	
HF		
HCl		
HBr		
HI		
(2)

(b)	Explain why HF has a higher boiling temperature than the other hydrogen halides and why there is an increase from HCl to HI.
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(3)
(Total 5 marks)

17.	A methanol molecule has 18 electrons in total.
(i)	Give the name and formula of a hydrocarbon with the same number of electrons.
Name ............................................
Formula

(1)
 
(ii)	Which intermolecular force depends to a large extent on the number of electrons present?
.....................................................................................................................................
(1)

(iii)	Would you expect methanol or your hydrocarbon in (i) to have the higher boiling point? Justify your answer.
.....................................................................................................................................
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(1)
 
(iv)	Draw a diagram to show the strongest intermolecular force between TWO molecules of the compound with the higher boiling point.
Indicate and give the value of the bond angle between these two molecules.
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(2)
(Total 5 marks)

18.	In hydrogen fluoride, HF, and water, H2O, the major intermolecular force is the hydrogen bond.
(a)	Draw a diagram to show the formation of hydrogen bonds between water molecules in ice. Show at least three water molecules in your diagram and any relevant polarity in the molecules.

(3)

(b)	Suggest why water has a higher boiling temperature than hydrogen fluoride.
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(2)
 
(c)	When hydrogen fluoride reacts with water it forms hydrogen ions. A lone pair of electrons on the water molecule joins with the hydrogen ion, H+, to produce the ion H3O+.
(i)	Draw a diagram to show clearly the shape of the H3O+ ion.

(1)
 
(ii)	Suggest an approximate value for the bond angle H—O—H in H3O+.
...........................................................................................................................
(1)

(iii)	The oxygen atom in water has two lone pairs of electrons. Suggest why the ion H4O2+ is not generally formed in acid solutions that contain the H+ ion.
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(1)
(Total 8 marks)

19.	(a)	Cooking fuels and petrol for car engines need to be gases or liquids which vaporise easily. This will be the case if the intermolecular forces are weak.
	Two common fuels are methane, CH4, and 2,2,4-trimethylpentane, C8H18.
	Electronegativity	
carbon	2.1	
hydrogen	2.5	
 
(i)	Explain the meaning of the term electronegativity.
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(2)

(ii)	The C—H bond in methane has some polarity but overall the molecule is non-polar.
	Explain why methane is a non-polar molecule.
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(2)
 
(iii)	Identify the strongest intermolecular force that exists between
2,2,4-trimethylpentane molecules in the liquid state.
...........................................................................................................................
(1)
 
(b)	In a car engine 2,2,4-trimethylpentane burns in air to produce carbon dioxide and water.
	The equation is
	2C8H18 + 25O2 → 16CO2 + 18H2O
	Molar mass of C8H18 = 114 g mol–1
 
(i)	Calculate the volume of oxygen needed to burn 700 g of 2,2,4-trimethylpentane.
[Assume the molar volume of a gas = 24.0 dm3 mol–1]

(3)

(ii)	Calculate the mass of carbon dioxide produced in the reaction in (i).

(2)
(Total 10 marks)

20.	This question is about three organic compounds with the following physical properties:
Compound	Formula	Boiling Point /K	ΔHοvap
/ kJ mol–1	
Butane	CH3CH2CH2CH3	273	6.9	
Propan-1-ol	CH3CH2CH2OH	371	14.8	
Propanone	CH3COCH3	330	9.0	
 
(a)	(i)	Name the intermolecular force present in all three compounds.
...........................................................................................................................
(1)
 
(ii)	Explain why this intermolecular force is likely to have a similar strength in butane and propan-1-ol.
...........................................................................................................................
...........................................................................................................................
(1)

(b)	(i)	Draw a ‘dot and cross’ diagram for the propan-1-ol molecule, showing outer electrons only.

(1)
 
(ii)	Name the strong additional intermolecular force between propan-1-ol molecules not present in the other two compounds.
...........................................................................................................................
(1)
 
(iii)	Using displayed formulae, draw a diagram to show this intermolecular force between two propan-1-ol molecules.

	State the values of the following bond angles:
	COH ..................
	The bond angle between the molecules ..................
(3)
 
(c)	(i)	Name the intermolecular force between propanone molecules that is not present in butane.
...........................................................................................................................
(1)

(ii)	Explain why you would expect propanone to mix with propan-1-ol.
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(2)
(Total 10 marks)

21.	What are the intermolecular forces in methanal, HCHO?
A	London forces only
B	hydrogen bonds and London forces
C	permanent dipole – permanent dipole only
D	permanent dipole – permanent dipole and London forces
(Total 1 mark)

22.	Which of the following substances is likely to be insoluble in water?
A	methanol, CH3OH
B	ethanol, CH3CH2OH
C	fluoromethane, CH3F
D	hydrogen fluoride, HF
(Total 1 mark)

23.	The following liquids have a similar number of electrons per molecule. Suggest which is likely to have the highest boiling point?
A	CH3CH2CH2CH2CH3
B	(CH3)3COH
C	CH3CH2CH(OH)CH3
D	CH3CH2CH2CH2OH
(Total 1 mark)

24.	(a)	(i)	Name the type of bonding that exists between water molecules.
...........................................................................................................................
(1)
 
(ii)	Draw a diagram to show this bonding. Use displayed formulae of two water molecules. Clearly mark and label the bond angle between the water molecules.

(2)
 
(b)	(i)	Draw the boron trichloride molecule, BCl3, making its shape clear. Mark the bond angle on your diagram.

(2)

(ii)	Explain why boron trichloride has this shape.
...........................................................................................................................
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...........................................................................................................................
(3)
 
(iii)	Explain why a B–Cl bond is polar.
...........................................................................................................................
...........................................................................................................................
(1)
 
(iv)	Explain why a BCl3 molecule is non-polar.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
 
(v)	Name the strongest intermolecular force between boron trichloride molecules.
...........................................................................................................................
(1)
(Total 11 marks)