STUDENT NUMBER: ____________________

PYMBLE LADIES' COLLEGE

2011 TRIAL HSC EXAMINATION Chemistry

General Instructions Reading time - 5 minutes Working time - 3 hours Write using black or blue pen Draw diagrams using pencil Board-approved calculators may be

used A data sheet and Periodic Table are

provided Write your Student Number at the top

of this page and other pages where indicated.

Total marks – 100

Section I Pages 3-17

75 marksThis section has two parts, Part A and Part B

Part A – 20 marks Attempt Questions 1-20 Allow about 35 minutes for this part

Part B – 55 marks Attempt Questions 21 – 33 Allow about 1 hour and 40 minutes for

this part

Section II Pages 18-19

25 marks Attempt ALL sections of Question 34 Allow about 45 minutes for this section

Multiple choice answer sheet

2011 Year 12 Chemistry Trial Examination

Select the alternative A, B, C or D that best answers the question.

Fill in the response space completely. If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer.

If you change your mind and have crossed out what you consider to be the correct answer, then indicate this by writing the word correct and drawing an arrow.

Start Here 1. A B C D

2. A B C D

3. A B C D

4. A B C D

5. A B C D

6. A B C D

7. A B C D

8. A B C D

9. A B C D

10. A B C D

11. A B C D

12. A B C D

13. A B C D

14. A B C D

15. A B C D

16. A B C D

17. A B C D

18. A B C D

19. A B C D

20. A B C D

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SECTION I Part ATotal Marks – 20 marksAttempt ALL questions

1. What type of reaction describes the polymerisation of glucose into cellulose?

A. AdditionB. Oxidation C. SubstitutionD. Condensation

2. In which of the following reactions does the metal atom show no change in oxidation state?

A. FeSO4 to FeCl3

B. MnCl3 to MnO2

C. NiO2 to Ni(OH)2

D. Cr(NO3)3 to Cr2(SO4)3

3. A student used the apparatus shown to determine the molar heat of combustion of butanol.

The following results were obtained.

Initial mass of burner 350.2gFinal mass of burner 348.6gInitial temperature of water 22.0◦CFinal temperature of water 43.0◦C

What is the molar heat of combustion calculated from this data?

A. 13.7 kJ mol-1

B. 22.0 kJ mol-1

C. 1014 kJ mol-1

D. 1624 kJ mol-1

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Thermometer

Calorimeter containing 250.0ml of water

Spirit burner containing butanol

4. C8H18 is a compound obtained from fractional distillation of crude oil. This compound then undergoes catalytic cracking.

C8H18 → C2H4 + C6H14

What are the systematic names of the products given in the equation?

A. Ethane and hexeneB. Ethene and hexaneC. Ethene and hexeneD. Ethane and hexane

5. What is the main advantage of using biopolymers instead of petroleum oil based polymers?

A. Biopolymers are biodegradableB. Biopolymers are easy to synthesise from celluloseC. Biopolymers are much cheaper than petroleum based polymersD. Biopolymers have superior properties compared to petroleum based polymers

6. Which set contains only stable nuclei? 2 12 238

A. 1H

6C 92U

16 39 12

B. 8O 19K 6C

65 18 24

C. 30Zn 8O 12Mg

14 16 1

D. 6C 8O 1H

7. What is the catalyst for conversion of ethanol to ethene?

A. Sulfuric acidB. ZeolitesC. Zeigler Natta D. Platinum

8. What is the conjugate acid of HCO3-?

A. CO2

B. CO32-

C. H2CO3

D. H2CO4

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9. 50 mL of 0.05 mol L-1 HCl is mixed with 30 mL of 0.08 mol L-1 of NaOH.

What is the pH of the resultant solution?

A. 1.9B. 2.9C. 4.0D. 7.0

10. A group of students produced a red solution by boiling red cabbage leaves in water. When dilute sodium hydroxide was added to the solution it turned purple, when dilute hydrochloric acid was added to the red solution, no colour change occurred.

Which of the following substances, when added, is most likely to cause the red solution to change colour?

A. Cleaning solution containing ammoniaB. Concentrated hydrochloric acidC. Orange juiceD. Vinegar

11. Equal volumes of four 0.1 mol L-1 acids were titrated with the same sodium hydroxide solution.

Which one requires the least volume of base for neutralisation?

A. Citric acidB. Ethanoic acidC. Sulfuric acidD. Phosphoric acid

12. Which of the following changes will always shift this equilibrium reaction to the right?

ΔH = +108 kJ

A. Adding a catalystB. Increasing the pressureC. decreasing the temperatureD. Adding more of the reactant

13. When calcium carbonate is decomposed it forms calcium oxide and carbon dioxide.

What mass of calcium carbonate will produce 50.0 L of carbon dioxide gas at 100 kPa and 0oC?

A. 2.00gB. 2.20gC. 200gD. 220g

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14. Which event in history was most affected by Haber’s discovery of an industrial method of producing ammonia?

A. First World WarB. Second world warC. The Irish Potato famineD. The industrialisation of Europe

15. What flame colour is produced by calcium ions in a flame test?

A. OrangeB. LilacC. GreenD. Red

16. A sample of water from a stream, suspected to be contaminated with ions, was analysed. The results of some tests on the water are recorded in the table.

Test Result

Add dilute HClAdd BaCl2

Add AgNO3

No changeNo changeWhite precipitate

What is the most likely contaminant in the water?

A. Carbonate ionB. Sulfate ionC. Chloride ionD. Phosphate ion

17. Which substances cause eutrophication in a waterway?

A. nitrogen and potassiumB. nitrogen and phosphorusC. calcium and bariumD. calcium and magnesium

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18. Which of the following correctly represents the reason that combustion reactions need to be monitored?

A. 2 C8H18 + 25 O2 → 16 CO2 + 18H2O

B. C8H18 + 6 O2 → 8 CO2 + 9H2

C. 2 C2H5OH + 7 O2 → 4 CO2 + 6 H2O

D. C8H18 + 10 O2 → 4 CO2 + 3 CO + C + 9 H2O

19. Which observation supports the idea that the Haber process is exothermic?

A. Yield of ammonia is increased by lower temperaturesB. Rate of production of ammonia is decreased by lower temperaturesC. Yield of ammonia is decreased by lower temperaturesD. Rate of production of ammonia is increased by lower temperatures.

20. When a 2.00g sample of fertiliser was analysed for sulfate by precipitating the sulfate with barium, the mass of precipitate obtained was 1.36g. What is the sulfate content of this sample?

A. 19.83%B. 27.99%C. 58.27%D. 68.00 %

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STUDENT NUMBER: ____________________Section I Part B -55 marks

Attempt Questions 21 - 33Allow about 1 hour and 50 minutes for this part. Answer the questions in the spaces provided.Show all relevant working in questions involving calculations.

MarksQuestion 21 [4 marks]

a) Identify a radioisotope used in medicine 1

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b) Describe the way in which the radioisotope is used and explain which properties make it particularly suited for this use. 3

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Question 22 [5 marks]

The diagram below represents a typical dry cell.

As the battery discharges, the following half reactions occur:

Zn → Zn2+ + 2e-

2NH4+ + 2MnO2(s) + 2e- → Mn2O3(s) + 2NH3 + H2O(l)

a) Identify the anode. 1

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b) Write the equation that represents the overall chemical reaction. 1

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c) Compare the cost and practicality and impact to society of either a dry cell or a lead acid cell to a cell of your choice. 3

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Question 23 [5 marks]During your course you conducted an experiment to monitor mass changes during the fermentation of glucose. Describe the experiment and comment on the mass changes you observed. 5

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Question 24 [4 marks]

Polystryrene is an important industrial polymer.

a) Give the systematic name for the monomer that makes this polymer. 1

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b) Draw a section of the polymer chain of polystyrene, showing three repeating units. 2

c) Describe one use of this polymer in terms of its properties. 1

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Question 25 [7 marks]Assess the impact of human sources of oxides of sulfur and nitrogen upon the environment, using chemical equations where appropriate. 7

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STUDENT NUMBER: ____________________Question 26 [5 marks]A student wanted to find the concentration of a solution of hydrochloric acid. She chose to titrate the hydrochloric acid with sodium carbonate (Na2CO3) which is a primary standard.

a) Why is sodium carbonate suitable as a primary standard? 2

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b) The steps involved in this titration are listed below.

A conical flask was rinsed with the dilute hydrochloric acid solution.

A pipette was rinsed with dilute hydrochloric acid solution immediately before using it to measure 25.00 mL of the dilute hydrochloric acid solution into the conical flask. Three drops of an indicator solution was added to this flask.

The burette was rinsed with some of the standard sodium carbonate solution immediately before using it to measure the volume of sodium carbonate solution needed to observe a colour change.

i) What mistake was made in carrying out this titration? 1

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ii) What effect would this error have on the calculated acid concentration? Why? 2

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Question 27 [3 marks]Explain, using examples, why acids are added to foods. 3

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Question 28 [3 marks]a) Name a salt which dissolves to give a solution that has a pH greater than 7. 1

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b) Explain why this solution has this pH. 2

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Question 29 [2 marks]

Why is the Arrhenius definition of an acid not entirely satisfactory? 2

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Question 30 [3 marks]

a) Identify ONE chemical occupation. 1

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b) Chemists need to collaborate as they collect and analyse data. Why? 2

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Question 31 [3 marks]

The water supply for Sydney households comes from Warragamba Dam.

Explain how this water is treated prior to reaching the tap in your house. 3

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Question 32 [4 marks]

A breakfast cereal was analysed for iron content using Atomic Absorption analysis. The graph below was obtained using standard samples.

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Iron ppm

abso

rban

ce

a) The cereal gave an absorbance reading of 0.45, what is the concentration of iron in the sample?1

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b) Atomic Absorption techniques are considered selective and sensitive. Explain why this is so. 3

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Question 33 [7 marks]

a) The Winkler method tests water for Dissolved Oxygen. The overall equation for the Winkler

process is:

O2 (aq) + 4H+ (aq) + 4 S2O32– (aq) → 2 S4O6

2– (aq) + 2H2O (l)

Calculate the dissolved oxygen content in parts per million in a sample of water if the average titre for a 250 mL sample of water using 0.0250 M thiosulfate (S2O3

2–) is 18.5 mL. 4

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b) Another sample of this water was kept for a BOD analysis. What does BOD stand for? 1

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c) What must be done with the original sample of water before it is analysed for dissolved oxygen if we want to test for BOD? 1

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d) What does the BOD measurement tell us? 1

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Section II

25 marks

Answer Question 34Allow about 35 minutes for this section.

Answer the question on the writing paper provided. Extra paper is available.

Show all relevant working in questions involving calculations.

Page

Question 34 Industrial Chemistry………………. …..…………………...19

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Question 34 – Industrial Chemistry (25 marks) Marks

a)

i) Identify ONE natural product, not a fossil fuel, for which shrinking world resources have made it necessary for us to find a replacement.

ii) Identify TWO reasons for the above named product being in short supply.

1

2

b)

The Ostwald process is used for making nitric acid from ammonia, and involves several equilibrium steps. One step in the process produces nitrogen dioxide according to the equation:

This reaction is exothermic.

A 1 L reaction vessel initially contained 0.25 mol NO and 0.12 mol O2.After equilibrium was established there was only 0.05 mol NO.

i) State the effect of increasing the pressure of this system.ii) Write the equilibrium constant expression for this reaction.iii) Calculate the value of K at this temperature.iv) What are TWO consequences of increasing the temperature of the

mixture at equilibrium?

1132

c)

i) Sulfur is required to produce sulfuric acid. Outline ONE use of sulfuric acid.

ii) Describe the processes used to obtain sulfur for the production of sulfuric acid and analyse potential environmental issues that may be associated with its collection.

2

5

d)

Explain why different products are produced by the electrolysis of aqueous and molten sodium chloride

4

e)

i) Identify the type of cell shown and describe the process to produce sodium hydroxide from brine (NaCl solution) using this cell.

4

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END OF PAPER

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