Chemistry Trial 2012 Exam Choice

1

Exam Choice

2012

TRIAL HIGHER SCHOOL

CERTIFICATE

EXAMINATION

Chemistry

General Instructions

Reading time 5 minutes

Working time 3 hours

Write using black or blue pen

Draw diagrams using pencil

Approved calculators may be used

Write your student number in the space provided

Student Number

Total marks 100

Section I Pages 2 - 22

75 marks

This 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 21-29

Allow about 1 hour and 40 minutes for this part

Section II Pages 23 - 31

25 marks

Attempt ONE Question from Questions 30-34

Allow about 45 minutes for this section

2

Section I

75 marks

Part A 20 marks Attempt Questions 1-20

Allow about 35 minutes for this part

Use the multiple-choice answer sheet.

Select the alternative A,B,C or D that best answers the question. Fill in the response oval

completely.

Sample: 2 + 4 = (A) 2 (B) 6 (C) 8 (D) 9

A B C D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the

new answer.

A B C D

If you change your mind and have crossed out what you consider to be the correct answer,

then indicate the correct answer by writing the word correct and drawing an arrow as follows.

A B C D

correct

3

1. Which of the following pairs of reactants could undergo a reaction to produce

2-chlorobutane in the absence of UV light?

(A) chlorine and 2-butene

(B) chlorine and butane

(C) hydrogen chloride and 2-butene

(D) hydrogen chloride and butane

2. Which of the following nuclear transformations could take place inside a nuclear

reactor, such as the one operating in Lucas Heights, NSW?

(A)

238

92 U

4

2 He +

234

90 Th

238

92 U

4

2 He +

234

90 Th

(B)

98

42 Mo +

1

0n

99

42 Mo

98

42 Mo +

1

0n

99

42 Mo

(C)

70

30 Zn +

207

82 Pb

278

116 Uub

70

30 Zn +

207

82 Pb

278

116 Uub

(D)

1

1H +

2

1H

3

2He

1

1H +

2

1H

3

2He

3. Four chemical reactions are shown below:

I MgO + 2HCl MgCl2 + H2O

II Cu + 2AgNO3 Cu(NO3)2 + 2Ag

III CuCO3 CuO + CO2

IV 4Fe + 3O2 2Fe2O3

Which of the reactions are redox reactions?

(A) II only

(B) II and IV

(C) I and II

(D) III and IV

4

4. Ethanol is currently used as an alternate car fuel in Australia.

Which one of the following identifies the source of this ethanol and the form in which

it is used in this application?

Source Form

(A) Crude Oil In pure form (100%) ethanol

(B) Crude Oil In fuel blends (mixed with petrol)

(C) Sugar cane In pure form (100%) ethanol

(D) Sugar cane In fuel blends (mixed with petrol)

5. A student set up the following apparatus to compare the heat of combustion of

methanol, ethanol and 1-propanol.

Which one of the following variables, if not controlled carefully, would have the

greatest effect on the validity of the procedure?

(A) The temperature to which the water is heated.

(B) The distance between the flame and the can.

(C) The volume of water heated.

(D) The initial temperature of the water.

5

6. The half-life of a radioisotope is the time it takes for the activity of the radioisotope to

decrease by one half.

The graph below shows how the % activity for a radioisotope changes over time.

Based on the graph above, which of the following could be a potential use for the

radioisotope?

(A) determining the age of fossils

(B) treating a cancerous brain tumour

(C) detecting smoke particles in a home smoke detector

(D) diagnosing a problem with blood flow through the heart

7. The table below describes some reactions of metals: W, X, Y and Z.

Metal Reaction in air Reaction with

water

Reaction with

dilute acid

W Reacts rapidly on

exposure to air

Reacts with cold

water to produce H2

H2 rapidly formed

X Reacts to produce

metallic oxide

No reaction H2 formed

Y Reacts slowly to

produce metal oxide

No reaction No reaction

Z Burns to produce

metallic oxide

Reacts with steam to

form H2

H2 is formed

Half-cells were made by placing each metal into 1M nitrate solutions of their ions.

Half-cells made of which two metals would produce the greatest voltage?

(A) W and X

(B) X and Z

(C) Y and W

(D) Y and Z

0

20

40

60

80

100

0 5 10 15 20

% activity remaining in

sample

Time (hours)

6

8. An element X forms an oxide which participates in the following reactions in aqueous

solution. Only one of the products formed is shown on the right.

Identify element X.

(A) Al

(B) Si

(C) P

(D) Ar

9. The following acid-base indicators change colour depending on pH as shown in the

following table.

What colour will the following indicators be if a few drops are added to 0.1 M

hydrochloric acid, and to 0.1 M acetic (ethanoic) acid (CH3COOH)?

Methyl orange

Bromothymol blue

HCl CH3COOH HCl CH3COOH

(A) Red Red Yellow Yellow

(B) Red Yellow Yellow Yellow

(C) Yellow Yellow Blue Blue

(D) Red Yellow Blue Blue

pH

Indicator

2 4 6 8 10 12 14

Methyl

orange red Yellow

Bromothymol

blue Yellow Blue

potassium carbonate Oxide of element X

reacts with

water

carbon dioxide

water

nitric acid

sulfur dioxide

7

10. A solution of a strong acid has a pH of 3.2. A student dilutes 10 mL of the solution to

1000 mL. What is the final pH?

(A) 3.2

(B) 4.2

(C) 5.2

(D) 6.2

11. The following graph shows the relationship between carbon number and boiling point

for three types of carbon compound.

Identify the type of carbon compound represented by lines X, Y and Z.

X Y Z

(A) Alkanes Alkanoic acids Alkanols

(B) Alkanols Alkanoic acids Alkanes

(C) Alkanes Alkanols Alkanoic acids

(D) Alkanoic acids Alkanols Alkanes

Boili

ng p

oin

t (o

C)

Carbon number

X

Y

Z

8

12. Which of the following pieces of equipment may have water left in it before it is

used?

X Y Z

(A) X only

(B) X and Y

(C) Y only

(D) Y and Z

13. A student mixes 1-butanol with propanoic acid in an esterification reaction.

Which of the following shows the structure of the organic product?

(A) (B)

(C) (D)

9

14. Which one of the following oxides can be prevented by ensuring that the combustion

of petrol in car engines occurs in an excess of oxygen?

(A) NO

(B) CO2

(C) SO2

(D) CO

15. Which of the following is not a use of ammonia?

(A) manufacture of explosives

(B) manufacture of detergents

(C) manufacture of fertilisers

(D) manufacture of paper

16. A student wants to determine the sulfate content of a fertilizer.

Following a typical procedure, they obtain the results shown below.

Mass of fertilizer used (g) 2.34

Mass of fertilizer that did not dissolve (g) 0.18

Volume of saturated BaCl2(aq) added (mL) 50

Mass of glass filter (g) 19.5

Mass of glass filter with dry BaSO4 (g) 21.6

What is the sulfate content of the fertilizer?

(A) 40%

(B) 50%

(C) 75%

(D) 90%

17. The molecules O2 and O3 are:

(A) diatomic

(B) compounds

(C) isotopes

(D) allotropes

10

18. Which of the following ions contributes to heavy metal pollution?

(A) Ca2+

(B) Pb2+

(C) Na+

(D) Fe3+

19. A solid sample was known to contain two calcium salts. In order to determine the

anions present, some tests were done on the solid, producing the following results.

Test done Results obtained

Observation of colour White

Addition of water to solid Solid partially dissolved

Addition of barium chloride to solution No precipitate

Addition of silver nitrate to solution White precipitate

Addition of HCl(aq) to solid Gas bubbles observed

Which two ions were present in the sample?

(A) PO43-

and SO42-

(B) Cl- and SO4

2-

(C) CO32-

and Cl-

(D) CO32-

and PO42-

20. In which layer of the earths atmosphere do oxides of sulfur occur naturally?

(A) troposphere

(B) stratosphere

(C) mesophere

(D) ionosphere

11

Section I (continued)

Part B 55 marks Attempt Questions 21 - 29

Allow about 1 hour and 40 minutes for this part

Answer the questions in the spaces provided.

Show all relevant working in questions involving calculations.

Question 21 (7 marks)

Ethanol can be produced from two different raw materials.

These processes are represented in the diagram below.

(a) Outline the physical and chemical changes that would occur in process 2,

including a balanced chemical equation with your answer.

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Question 21 continues on page 12.

Marks

3

CRUDE OIL ETHANOL

CELLULOSE ETHANOL Process 1

Process 2

12

Question 21 (continued)

(b) Discuss the benefits and limitations of producing ethanol from Process 1

compared to producing it from Process 2.

Include a relevant equation with your answer.

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Marks

4

13


A chemistry student drew the following diagram to demonstrate their understanding

of the reaction to form a short segment of polyethene, and the composition of

polyethene.

With reference to the diagram only, assess the students understanding of polyethene and the reaction that forms it.

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Marks

3

ethene ethene ethene ethene ethene 4

14


As part of your studies of electrochemistry, you studied the chemical composition

and features of either a dry cell or a lead-acid battery.

(a) Identify the electrolyte used in the cell that you studied.

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(b) Explain how the battery you studied has impacted on society and the

environment.

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Marks

1

3

15


Half-cells made from three metals (X, Y and Z) and their solutions were coupled

with a copper half-cell under standard conditions, as shown in the diagram below.

The voltage produced and the polarity of the copper electrode, were recorded in a

table below.

Metal Cell voltage produced by coupling

metal half- cell with Cu half-cell

Polarity of Copper

X 0.31 +ve

Y 1.14 -ve

Z 0.42 -ve

(a) Outline the function of the salt bridge in the cells above.

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(b) Using the data provided, rank the metals (X, Y, Z and Cu), in increasing

order of reactivity.

Explain how you arrived at your answer.

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Marks

1

3

X

X2+

Y

Y2+

+

Z

Z2+

+

16


A student used temperature change during neutralization to calculate the

concentration of hydrochloric acid. The method they used was:

1. 1L of 0.145 M NaOH and 1L of HCl were allowed to sit at room temperature for 60 minutes.

2. 25.0 mL of 0.145 M NaOH was added to a polystyrene cup using a volumetric pipette.

3. The temperature of the NaOH(aq) was measured using a thermometer. 4. 10.0 mL of HCl was added to the cup using a volumetric pipette. 5. The highest temperature reached was measured. 6. Steps 1 4 were repeated with 20, 30, 40, 50 and 60 mL of HCl.

The results they obtained are shown in the table below.

V (HCl) added vs temp. when neutralizing 0.145 M NaOH.

Volume of HCl added (mL) Max. temperature reached (oC)

0 21.0

10 28.0

20 35.0

30 35.0

40 32.5

50 30.0

60 27.5

(a) Use the grid below to graph the data above.

(b) Draw two straight lines through the points and extend them until they cross.


Marks

3

1

Tem

pera

ture

(0C

)

Volume HCl added (mL)

dd

0

17


(c) What volume of HCl was required to completely neutralize the NaOH?

On your graph, show how you obtained this value.

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(d) Calculate the concentration of the HCl.

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(e) Assess the validity of this experiment.

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Marks

1

2

3

18


Nitric acid and acetic (ethanoic) acid are common laboratory acids, and there are

important similarities and differences in their chemistry.

(a) In the boxes below, draw simple particle diagrams of each acid to show the

extent of their ionization.

(b) Nitric acid can be a component of acid rain.

Explain how nitric acid forms in the atmosphere, and outline the effects of

acid rain. Include a relevant chemical equation in your answer.

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(c) Nitric acid forms neutral salts, whereas acetic acid forms basic salts.

With the aid of equations, explain why acetate salts are basic.

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Marks

2

3

2

19


(d) Acetic acid can be used to prepare esters, whereas nitric acid cannot.

Outline the importance of reflux as a technique in esterification.

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Ammonia production has remained one of the most important processes since its

industrialization in 1913.

Explain how the conditions used in the process maximize rate and yield, and assess

the importance of the catalyst.

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Marks

2

5

20


Relatively recent human activity has reduced the concentration of ozone in the

upper atmosphere, with serious consequences.

(a) The molecules responsible for ozone depletion are CFCs.

(i) Give the systematic name of the compound below.

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(ii) Describe how a compound such as that shown in part (i) can destroy

ozone. Support your answer with chemical equations.

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(b) Outline the consequences of ozone depletion in the upper atmosphere.

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Marks

1

3

2

21


A concerned analytical chemist decided to test the water quality in a stream near her

home. She used the following information to help her.

Marks

pH 3 4 5 6 7 8 9 10

Mg2+

Maximum availability Forms insoluble

carbonates

PO43-

Insoluble salts form with Fe

3+

and Al3+

Maximum availability

Ca2+

forms insoluble phosphate

NO3- Not available to plants Maximum availability

Cu2+

Maximum availability Forms insoluble

phosphates

She collected a 500 mL sample of water. The tests she carried out, and her results,

are shown in the table below.

Procedure Result

- bubble O2(g) into the water at 250C to

saturate it with oxygen: [O2] = 0.009g/L - leave for five days and perform Winkler titration

1.1 x 10-5

mol O2 remains

Insert pH probe to test pH pH = 7.5

Add Na2S(aq) to a sample Black solid forms

Add soap to a sample No froth observed

(a) Assess the health of the waterway in terms of biochemical oxygen demand

(BOD), and one of the following factors:

- Hardness - Eutrophication

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4

22


(b) Atomic absorption spectroscopy proved to be very useful to the chemist,

allowing her to determine accurate concentrations of some species in the

waterway.

(i) Identify one species from Table 1 that can be analysed using AAS.

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(ii) Outline how the chemist would have obtained a calibration curve

before testing the water sample.

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Marks

1

2

23

Section II

Total marks: 25

Attempt ONE question from Questions 30-34

Allow about 45 minutes for this Section.

Answer the questions in a writing booklet. Extra writing booklets are available.

Show all relevant working in questions involving calculations.

Page

Question 30 Industrial Chemistry ........................................................................ 24 - 25

Question 31 Shipwrecks, Corrosion and Conservation ....................................... 26 - 27

Question 32 The Biochemistry of Movement ..................................................... 28

Question 33 The Chemistry of Art ...................................................................... 29

Question 34 Forensic Chemistry ......................................................................... 30 - 31

24

Question 30 - Industrial Chemistry (25 marks)

(a) Many industrial processes involve equilibrium reactions, and manipulating

equilibrium conditions is an important part of industrial chemistry.

(i) Identify the experimental variable that changes the value of the

equilibrium constant.

(ii) The water-gas shift reaction is a useful industrial method for the

production of hydrogen gas, some of which is used to provide

hydrogen for the Haber process. The equation for the process is:

CO(g) + H2O(g) CO2(g) + H2(g)

A flask initially containing only 1.5 M CO and 2.5 M H2O was found

to contain 0.5 M CO2 at equilibrium.

Calculate the equilibrium constant K for the reaction.

(iii) The industrial production of SO3 is also an equilibrium reaction.

Outline how the conditions used maximize the rate and yield of SO3.

(b) You have investigated the electrolysis of aqueous NaCl in the laboratory.

Explain the difference between electrolytic and galvanic cells, and use the

information below to explain the different electrolysis products of NaCl(l)

and NaCl(aq).

Support your answer by describing the results you obtained in your own

investigation.

Reaction E0 (V)

Na+ + e

- Na -2.71

H2O + e- H2 + OH

- -0.83

O2 + 2H+ + 2e

- H2O 1.23

Cl2 + 2e- Cl- 1.36

(c) (i) Outline the cleaning action of soap, and include a labelled diagram of

a micelle in your answer.

(ii) Describe the structure and properties of the two types of synthetic

detergents that have been developed to meet the increasing demand

for soaps.


Marks

1

2

3

6

3

4

25


(d) Environmental considerations have become increasingly important in

chemical industry, and the production of sulfuric acid and sodium

carbonate both have environmental impacts.

(i) Outline an environmental issue associated with the extraction of

sulfur.

(ii) Discuss the way in which environmental factors influence the location

of a Solvay Plant.

Marks

2

4

26

Question 31 - Shipwrecks, Corrosion and Conservation (25 marks)

(a) (i) Our understanding of electron transfer reactions and their potential

applications developed as a result of the contributions by a number of

scientists.

Identify the scientist who formulated two significant laws relating to

the quantitative aspects of electrolysis.

(ii) A student wished to apply the process of electrolysis to produce a

sample of chlorine gas, starting with a solid sample of sodium

chloride.

Describe some of the factors that the student must consider in order to

carry out this task.

(iii) In 1807, Sir Humphrey Davy used the recently invented voltaic pile to

isolate a pure sample of sodium from sodium hydroxide via

electrolysis.

Calculate the minimum voltage required to operate an electrolytic cell

for the isolation of sodium, including relevant half equations and the

net ionic equation that occurs as it operates.

(b) As part of your practical studies you have conducted an experiment to

compare the rate of corrosion of iron in solutions of varying acidity.

Describe the procedure you followed and apply what you learned in the

investigation to explain why steel corrodes at fast rates at oceanic depths.

(c) Electron-transfer chemistry plays a role in both the corrosion of artefacts

submerged in a shipwreck as well as in their restoration.

(i) Explain, using appropriate half-equations, the chemistry involved in the corrosion of an iron-based artefact in a shipwreck at relatively

shallow depths.

(ii) A silver spoon, heavily encrusted with calcium carbonate deposits,

was found in a different shipwreck which had been submerged for

many years. After removing the calcium carbonate, the spoon was

found to be covered by a black deposit.

Justify a procedure which could be used to clean the spoon of both the

calcium carbonate and the black deposit. Include relevant equations in

your answer.


Marks

1

2

3

6

3

4

27


(d) (i) A student had read that connecting the hull of a steel ship with certain

metals could protect it from corrosion.

Design a valid investigation which would compare the effectiveness of

some common metals in reducing the corrosion of iron submerged in

water.

(ii) Describe the chemistry involved in the type of protection investigated

in (i) above.

Marks

4

2

28

Question 32 - The Biochemistry of Movement (25 marks)

(a) (i) Identify the two locations of glycogen storage in humans.

(ii) Identify the structure of glycogen and outline how glycogen is formed.

(iii) Account for the different solubility in water of glycerol and TAGs,

supporting your answer with the structural formula of glycerol.

(b) Assess the importance of the structure of proteins and describe how this can

be disrupted. Illustrate your answer with the results of your own first-hand

investigation into enzyme activity.

(c) Carbohydrates and fats are important biological molecules with a number

of functions, including being fuels for cells.

(i) Describe how muscle cells contract and identify the role of ATP in this

process.

(ii) Describe the aerobic metabolism of glucose and its role in ATP

production.

(d) Gentle exercise and sprinting are different in terms of energy requirements,

and metabolic products such as lactic acid.

(i) Lactic acid is also known by two other names.

Identify these two names.

(ii) Compare and contrast Type 1 and 2 muscle cells and the way in which

their energy requirements are met, and explain why muscle cramps can

result from high-intensity exercise.

Marks

1

2

3

6

3

4

2

4

29

Question 33 - The Chemistry of Art (25 marks)

(a) The copper based pigment malachite contains combined copper in the form

CuCO3 and Cu(OH)2.

(i) Write the electron configuration of copper as it would occur in both

CuCO3 and Cu(OH)2.

(ii) Apart from the metal ion present, explain how TWO other variables

may affect the colour of a mineral.

(iii) Cu2+

ions form a complex ion with chloride ions as represented by the

following equation:

Cu

2+ + 4Cl

- [CuCl4]

2-

Describe the bonding between the copper and chloride ions in the

complex ion. Include a Lewis diagram to assist in your description.

(b) You have investigated the phenomena of flame colours for various metal

ions, one of which was sodium.

Describe the procedure you followed in your investigation and account for

the flame colour observed for sodium using an appropriate atomic model

and an energy level diagram.

(c) For thousands of years, humans have used naturally occurring minerals to

depict various images in works of art.

(i) Describe the properties of some named minerals that make them

useful for this purpose.

(ii) Explain some factors that have resulted in changes in the type of

substances used as pigments in art works over the past 200 years,

using specific examples with your answer.

(d) The current atomic model can be used to explain many trends in the

properties of elements as they are placed in the periodic table.

(i) Define the term electronegativity and outline the trend in

electronegativity down a group.

(ii) Using elements in Period 2 as examples, analyse the relationship

between trends in first ionization energy and electronegativity across

the period, and account for the trends described at the atomic level.

Marks

1

2

3

6

3

4

2

4

30

Question 34 - Forensic Chemistry (25 marks)

(a) Carbohydrates are a vital group of compounds which are equally important

in the animal and plant kingdom.

(i) Carbohydrates can be represented by the general formula Cx(H2O)y.

Write the formula for sucrose using this format.

(ii) Identify the roles of cellulose, starch and glycogen in living systems.

(iii) Describe the chemical difference between reducing and non-reducing

sugars and illustrate your answer with the results of your own first-

hand investigation to distinguish between these two types of sugars.

(b) A range of spectroscopic techniques is available to forensic chemists.

Explain how line emission spectra and mass spectra are obtained including

the underlying chemistry, and assess their usefulness to a forensic chemist.

(c) Forensic chemists use the analysis of various types of inorganic and organic

material to aid in the investigation of crimes.

(i) A laboratory technician finds that the labels have fallen off four

bottles of colourless liquids in their storeroom. The labels that they

find on the shelf are shown below.

Design a series of chemical tests that would allow these liquids to be

distinguished in the school laboratory, and identify the underlying

chemistry.

(ii) Describe the structure and composition of DNA, and explain why

DNA analysis is so useful to a forensic chemist.


Marks

1

2

3

6

3

4

0.1 M Na2CO3 1-octene

1-octanol octane

31


(d) (i) Identify the type of compound shown below. Draw and label the major

functional groups it contains.

(ii) With reference to the compound shown in d(i), describe the structure

of proteins, and explain how their origins may be determined using

electrophoresis.

Marks

2

4

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Chemistry Trial 2012 Exam Choice