SECTION A: Multiple-Choice Questions (30%)

1. There are TWO sections, A and B, in this paper You are advised to finish Section A in about 35 minutes.
2. Section A consists of multiple-choice question paper, while Section B contains conventional questions printed separately in Question-Answer Book B.
3. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to Section B should be written in the spaces provided in Question-Answer Book B. The Answer Sheet for Section A and the Question-Answer Book for Section B must be handed in separately at the end of the examination.
4. Atomic numbers and relative atomic masses of elements can be obtained from the Periodic Table printed on last page.

SECTION A: Multiple-Choice Questions (30%)

1.Boron consists of two isotopes. The table below lists relative abundance of these two isotopes.

The relative atomic mass of boron (correct to 1 decimal place) is

A.10.4.B.10.6.C.10.8.D.11.0.

2.Which of the following diagrams can represent a mixture of two compounds?

(In these diagram,  and  represent a nitrogen and an oxygen atom respectively)

P.T.O.

3.Which of the following compound is/are ionic compound(s)?

(1) AgCl(2)SCl2(3) NH4Cl

A.(1) onlyB. (2) onlyC. (1) &(2)D. (1) & (3)

4.A metal X has no observable changes upon the addition to cold water. However, colourless gas bubbles evolved when it was put into dilute hydrochloric acid. What will happen when it was put into a copper(II) sulphate solution?

A.There will be no observable changes.

B.Colourless gas bubbles will evolve.

C.The colour of solution will become blue from colourless.

D.A brown solid will be deposited on the surface of metal X.

1. Which of the following situation will colourless gas bubbles evolve vigorously?

A.Sodium carbonate solid is put into solid citric acid.

B.Sodium hydroxide solution is mixed with dilute hydrochloric acid.

C.Aluminium ribbon is put into dilute hydrochloric acid

D.Zinc solid is put into a beaker of cold water.

6. If 2.0 g of CO gas contain x atoms, how many atoms are present in 1.0 g of hydrogen gas?

A.2xB.7/2xC.7xD.14x

7.A salt, KCl˙MgCl2˙nH2O, contains 38.9% by mass of water of crystallization. What is the value of n?

A3B4C5D6

8.22.0 g of propane are allowed to react with 57.6 g of oxygen. What is the mass of carbon dioxide produced

A47.5 gB66.0 gC69.1gD237.6g

9.Which of the following metal oxides can be reduced to the metal when heated with carbon?

(1)aluminium oxide(2)lead(II) oxide(3)iron(III) oxide

A.(1) onlyB.(2) onlyC.(1) & (3) onlyD.(2) & (3) only

1. 50 cm3 of the both acids have the same pH.
2. They have different temperature rise when they are reacted with 50 cm3 1M sodium hydroxide solution completely.
3. 50 cm3 1M sulphuric acid has a pH double of 50 cm3 1M hydrochloric acid.
4. 50 cm3 1M hydrochloric acid has a pH double of 50 cm3 1M sulphuric acid.

11.A sample of concentrated sulphuric acid has a density of 1.83 g cm-3 and contains 94.0% of sulphuric acid by mass. What is the concentration (correct to one decimal place) of sulphuric acid in the sample?

A.17.5 MB.18.3 MC.18.7 MD.19.8 M

12.A black powder is suspected to be carbon or a mixture of carbon and copper(II) oxide. Which of the following methods can be used to identify the black powder?

(1)adding dilute sulphuric acid to the powder

(2)adding sodium hydroxide solution to the powder

(3)heating the powder strongly

A.(1) onlyB.(2) onlyC.(1) & (3) onlyD.(2) & (3) only

13.The formula of a metal carbonate is X2CO3. 100 cm3 of a solution containing 0.69 g of the carbonate requires 50 cm3 of 0.20 M hydrochloric acid for complete reaction. What is the relative atomic mass of metal X?

A.19.0B.23.0C.39.0D.78.0

14. Which of the following pairs of solution would give a white precipitate when they are mixed?

A. Sodium carbonate and hydrochloric acid

B.Lead(II) nitrate and hydrochloric acid

C.Iron(II) nitrate and sodium hydroxide

DIron(III) nitrate and sodium hydroxide

15. The following are the titration results for the reaction of 20.0 cm3 of a sodium hydroxide with 0.150 M nitric acid, HNO3:

Burette readings1st 2nd3rd

Final reading (cm3)32.50 33.4032.70

Initial reading (cm3)1.00 3.30 2.40

What is the molarity of sodium hydroxide solution?

A.0.224MB.0.227 MC.0.230 MD.0.233 M

16.What volume of water should be added to 200 cm3 of 2 M hydrochloric acid to change the acid concentration to 0.5 M?

A.400cm3B.600cm3C.800cm3D.1000cm3

17.When washing the apparatus for titration, which of the following should be washed with the deionized water only?

(1)conical flask(2) pipette(3) burette

A.(1) onlyB.(2) only C. (1) and (2)D. (1) and (3)

P.T.O.

18.What is the IUPAC chemical name of the following compound?

A.2-methylpentanedioic acidB.2-methylpentandioic acid

C.4-methylpentanedioic acidD.4-methylpentandioic acid

19.10 cm3 of 1M acid requires 30 cm3 of 0.5 M sodium carbonate solution for complete reaction. What is the basicity of the acid?

A.1B. 2C.3D.4

20.25.0 cm3 of 1.00 M hydrochloric acid is mixed with 25.0 cm3 of 0.500 M sodium hydroxide solution. What is the molarity of the resulting sodium chloride solution?

A.0.250 MB.0.500 MC.0.750 MD.1.00 M

21.What is the molarity of the chloride ions in 0.500 g cm-3 calcium chloride solution?

A.0.00450 MB.0.00901 MC.4.50 MD.9.01 M

22. Which of the following are correct statements describing alkenes?

(1)It decolourizespurple acidified potassium permanganate solution.

(2)It burns with a more sooty flame than alkanes with similar molecular mass.

(3)It has a general formula of CnH2n+2.

A.(1) and (2)B. (1) and (3)C. (2) and (3)D. (1), (2) and (3)

23.Which of the following is NOT the appropriate substance for preparing magnesiumsulphate by directly mixing with dilute sulphuric acid?

A. MgB. MgCO3C. Mg(OH)2D. Mg(NO3)2

24.Which of the following measures can reduce the emission of sulphur dioxide from a factory using diesel fuel?

(1)the installation of catalytic converters

(2)the installation of scrubbers

(3)the installation of electrostatic precipitators

A.(1) onlyB.(2) onlyC.(1) & (3) onlyD.(2) & (3) only

To be continued

25.Which of the following concerning the reaction of methane with bromine is/are correct?

(1)It is an addition reaction

(2)It is a substitution reaction

(3)It can occur at room temperature in the dark.

A.(1) onlyB.(2) onlyC.(1) & (3) onlyD.(2) & (3) only

Directions: Each question below (Question number 26 to 30) consists of two separate statements. Decide whether each of the two statements is true or false; if both are true, then decide whether or not the second statement is a correct explanation of the first statement. Then select one option from A to D according to the following table:

1. Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
2. Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
3. The 1st statement is false while the 2nd is true.
4. Both statements are false.

END OF SECTION A

SECTION B: Question-Answer Book (70%)

1. Answer all questions. Write your answers in the space provided.
2. An asterisk(*) has been put next to the question where one mark will be awarded for effective communication.

1.The following table has given some information about W, X, Y and Z which represent particles of some elements. These particles are either atoms or ions.

(a)In which group of the Periodic Table should W be placed? Explain your answer.

(2 marks)

(b)(i)What is the relationship between W and X?

(ii)What is the relationship between Y and Z?

(2 marks)

(c)Molecules of Y and of Z are both diatomic.

(i)Draw an electron diagram of a molecule of Y, showing electrons in the outermost shells only.

(ii)Do molecules of Y and of Z have the same chemical properties? Explain your answer.

(2 marks)

2. Consider the following organic molecules:

(a)Give the IUPAC name of A.

(1 mark)

(b)Which of the above organic molecules can undergo addition polymerization?

(1 mark)

(c)For those molecule(s) which can undergo addition polymerization, write the equation for each reaction.

(2 marks)

(d)Name the polymer made from A and give a daily use of the polymer.

(2 marks)

(e)The following flow chart shows the preparation of compound A mentioned above:

(i)Suggest an industrial method to produce ethene.

(ii)Draw the structural formula of compound X.

(2 marks)

3.A student determines the molecular formula of a hydrocarbon W with the following set-up:

A known mass of W was heated in excess oxygen. The following results were obtained.

Mass of U-tube A before the experiment = 70.435 g

Mass of U-tube B before the experiment = 67.544 g

Mass of U-tube A after the experiment = 84.493 g

Mass of U-tube B after the experiment = 101.908 g

(a)What are the functions of

(i)anhydrous calcium chloride and

(ii)sodium hydroxide pellets?

(2 marks)

(b)Determine the empirical formula of W.

(3 marks)

(c)The relative molecular mass of W is 308.0. What is the molecular formula of W?

(2 marks)

(d)State ONE assumption for the above experiment.

(1 mark)

4. A student is going to prepare silver bromide in the laboratory.

(a)Write an ionic equation, with state symbols, for the reaction involved.

(2 marks)

(b)Draw the electron diagram (showing the outermost shell electrons only) of silver bromide.

(1 mark)

*(c)Outline an experimental procedure for the preparation of silver bromide.

______

______

______

______

(5 marks)

(d)0.01 mol silver ions give 1 g of silver bromide. Calculate the percentage yield of preparation of silver bromide.

(2 marks)

5. The sour taste of citric fruits is mainly due to citric acid which is a weak acid

(a)What is the meaning of the term 'weak acid'?

(1 mark)

(b)Given that citric acid is a tribasic acid, H3X. Write a chemical equation for the complete neutralization of citric acid by sodium hydroxide solution.

(1 mark)

(c)In a titration experiment to determine the concentration of citric acid in orange juiceusing phenolphthalein as indicator, 25.0 cm3 of a sample of orange juice required 10.0 cm3 of 0.30 M sodium hydroxide solution for completely neutralization.

(i)Given that the relative molecular mass of citric acid is 192, calculate the concentration of citric, in g dm-3, in the sample of orange juice.

(ii)State ONE assumption in your calculation in (c)(i).

(iii)State the colour change of end point.

(6 marks)

6.The fumes emitted from a factory using diesel fuel contain several gaseous pollutants. One of these pollutants, Z, which is brown in colour

(a)(i)What is Z?

(ii)State ONE effect of Z on the environment.

(iii)Suggest ONE way to reduce the amount of Z in the fumes.

(3 marks)

(b)(i)Suggest ONE other pollutant which causes acid rain.

(ii)Write a chemical equation for your answer in (b)(i) to cause acid rain.

(2 marks)

7.Describe a chemical test (flame test is not accepted) that allows you to distinguish the following pairs of compounds:

(a) sodiumsulphate solution and magnesium sulphate solution

(2 marks)

(b) solid ammonium chloride and solid calcium chloride

(2 marks)

8.The table below lists some physical properties of lead, bromine and lead(II) bromide.

(a)Explain the difference in melting points between bromine and lead(II) bromide.

(2 marks)

(b)Explain the difference in electrical conductivity between lead and lead(II) bromide in the solid state.

(2 marks)

(c)In the setup below, a small crystal of potassium permanganate was placed at the centre of a piece of filter paper soaked with sodium sulphate solution.

(i)A purple patch was later found on the filter paper near electrode P. What does it show?

(ii)Suggest how one can confirm the appearance of colour spot is not caused by diffusion.

(3 marks)

9.Two samples of calcium carbonate of equal mass were added to 50 cm3 of 1 mol dm-3 hydrochloric acid and 50 cm3 of 1 mol dm-3ethanoic acid separately. The acid was in excess in each case.

(a)Write an ionic equation for the reaction between calcium carbonate and dilute hydrochloric acid.

(1 mark)

(b)Give one similarity and one difference between the two reactions.

(2 marks)

(c) If 40.0 g of calcium carbonate reacted with excess hydrochloric acid, determine the mass of carbon dioxide gas released.

(2 marks)

10.Crude oil is a mixture consisting mainly of alkanes. Fractional distillation of crude oil gives different petroleum fractions. The table below lists the length of carbon chain of the alkanes in some of the fractions.

(a)Describe the principle underlying the fractional distillation of crude oil.

(2 marks)

(b)(i)Explain why the global demand for petrol is greater than that for kerosene.

(ii)Cracking kerosene can produce petrol. State the conditions required for the cracking process.

(3 marks)

(c)In Hong Kong, naphtha instead of coal is used to manufacture town gas.

(i)State ONE advantage of using naphtha instead of coal to manufacture town gas.

(You are NOT required to consider the price of the materials)

(ii)Explain why an additive with a foul smell is added to town gas before it is delivered to the consumers.

(3 marks)

(d)Give ONE use of fraction X in cars.

(1 mark)

Baptist Lui Ming Choi Secondary School

Final Examination (2013-2014)

Chemistry

SECTION A: Multiple-Choice Questions (30 marks)

SECTION B: Question-Answer Book (70 marks)

1. (a) Group II [1] because W has 2 electrons in its outermost shell. [1]

(b) (i) X is the cation of W [1]

(ii) Isotope [1]

(c) (i)

[1]

(ii) Yes. They have the same no. of electrons [1]

(Do not accept same no. of outermost electrons)

2. (a) Chloroethene[1]

(b) A and C[1]

(c) A:

[1]

C:

[1]

(d)Polyvinyl chloride/ polychloroethene [1]

It can be used to make pipes/ shower curtains/ tablecloths/ raincoats/ water hoses/ electrical wire insulation. [1]

(e)(i) Cracking of larger alkanes [Does not accept cracking] [1]

(ii) [1]

P.2

3. a)(i)To absorb the water / water vapour produced. [1]

(ii)To absorb the carbon dioxide produced. [1]

b)

∴the empirical formula of W is CH2.[1]

c)Let (CH2)n be the molecular formula of W.
n(12.0 + 2 x 1.0)= 308.0[1]

n= 22∴the molecular formula of W is C22H44.[1]

d)W burnt completely in oxygen to give carbon dioxide and water./
All the water and carbon dioxide produced were absorbed completely by anhydrous calcium chloride and sodium hydroxide pellets respectively. [1]

4. (a) Ag+ (aq) + Br—(aq)AgBr(s) [1+1]

(b)

[1]

(c) Firstly, mix equal volume and molarity of silver nitrate solution and sodium bromide solution into a beaker. Stir the solution well until precipitation occurs. [1]

Secondly, obtain the solid residue by filtration. [1]

Then, wash the residue with plenty of distilled water to remove any soluble impurities. [1]

Lastly, dry the crystals using filter papers. [1]

Communication mark [1]

(d) Theoretical yield is 0.01 mol

Actual yield = 1 / (107.9 + 79.9) = 0.00532 mol [1]

% yield = 0.00532 / 0.01 * 100% = 53.2% [1]

P.3

(iii) it changes from colourlessto pink. [1]

1. (a) (i)nitrogen dioxide [1]

(ii)Attacks respiratory system/produces acid rain/causes photochemical smog [1]

(iii)Installation of catalytic converter [1]

(b)(i)sulphur dioxide [1]

(ii)SO2 + H2O H2SO3 [1]

7. (a) Add sodium hydroxide solution /potassium hydroxide solution to each .[1]

Sodium sulphate shows no visible changes while magnesium sulphate gives a white precipitate. [1] (must state the difference)

(b)Heat the two solids with sodium hydroxide/potassium hydroxide/alkali.[1]

Ammonium chloride will give a colourless gas with a pungent smellwhile calcium chloride does not. [1]

8

(a)

P.4

8. (b)

(c)(i) It shows that there are mobile ions for conducting electricity.

[Cancelled, all are awarded 1 mark]

(ii)Reverse the polarity of two electrodes and repeat the experiment. [1] If the purple spot appeared near electrode Q [1], then the motion of ions is dependent on the polarity of electrode instead of the consequence of diffusion.

9.

(a)CaCO3 (s) + 2H+ (aq) ---- > Ca2+ (aq) + CO2(g) + H2O (l)[1]

(b) Similarity: [1]

- Colourless gas bubbles observed for both reactions

-Same no. of moles of acid is required for the complete reaction

Differences: [1]

- The rate of evolution of gas bubbles for the reaction between hydrochloric acid and calcium carbonate is higher than that between ethanoic acid and calcium carbonate.

(c) No.of moles of CaCO3 = 40/100 = 0.4 mol[1M]

No of moles of CaCO3 = no of moles of CO2 = 0.4 mol

Mass of CO2 = 0.4 x [12+16*2]

=17.6 g [1](zero for no unit.)

10.

(a) Different alkanes have different boiling points and therefore they become vapour at different temperatures.[1]

Vapour of alkanes with low relative molecular size condenses at lower temperature[1] /vapour of alkanes with high relative molecular size condenses at higher temperature.

(b)(i) Petrol is mainly used as fuel for motor cars. [1] The rapid growth in the number of motor

cars makes the demand for petrol much greater than for kerosene. [1]

(ii)Heating under pressure in the absence of air [1] / Heating in the presence of a catalyst in the absence of air at a much lower pressure.

(c)(i) It is easier to transport /store naphtha [1] / less air pollutants

(ii) To alert consumers of the leakage of town gas [1] / which contains carbon monoxide [1] which is toxic

(d)Lubricating oil [1]