Hsc Chemistry Past Paper
Student Number
Mark / 100
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 a Periodic Table are provided. Write your Student Number at the top of this page and those of pages 10 and 11.
Total Marks – 100 Section I Pages 2 – 24
Confidential Keep Secure
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 – 32 •Allow about 1 hour and 40 minutes for this part Pages 25 – 26
Section II 25 marks
•Attempt Question 33 •Allow about 45 minutes for this section …show more content…
JRAHS TRIAL HSC Exam Chemistry 2011
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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 on page .....
Mark your answers on the ANSWER grid on page 10. ________________________________________________________________________________
JRAHS TRIAL HSC Exam Chemistry 2011
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Part A Multiple Choice Use the multiple – choice answer sheet for Questions 1 – 20 . 1. Which of the following chemicals would decolourise bromine water the quickest in the presence of UV light? (A) (B) (C) (D) Concentrated H2SO4 Cyclohexane 1-hexene 1-hexanol
2.
What products would result from the catalytic cracking of a 15-carbon alkane? (A) (B) (C) (D) One alkane and one alkene One alkanoic acid and one alkanol Two alkanes Two alkenes
3.
The molar heat of combustion of ethanol is 1367 kJ mol-1. A 2.510 g sample of ethanol was combusted in heating a certain mass of water from 25 oC to 45oC. 80% of the heat released was absorbed by the water. What was the quantity of water heated? (A) (B) (C) (D) 712.7 g 713.8 g 890.9 g 892.2 g
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4.
A sample was tested for its approximate pH using several indicators. The results are given in the table. Indicator bromothymol blue litmus methyl orange phenolphthalein What is the most accurate estimate for the pH of the sample? (A) (B) (C) (D) Between 6.0 and 6.3 7.0 Between 7.5 and 8.0 Between 9.0 and 14.0 Colour of indicator in sample blue blue yellow colourless
5.
Why is radon-226 a radioactive isotope? (A) (B) (C) (D) Its mass number is greater than 83. It has more neutrons than protons. The ratio of neutrons to protons is not 1:1. The ratio of neutrons to protons is too low.
6.
The half-equations for the vanadium redox cell are given below. VO2+ (aq) + 2H+ + e- VO2+ (aq) + H2O (l) V2+ (aq) V3+ (aq) + eWhat is the change in the oxidation state of vanadium for the reduction half-equation in this cell? (A) (B) (C) (D) 2+ to 0 3+ to 2+ 2+ to 3+ 5+ to 4+
JRAHS TRIAL HSC Exam Chemistry 2011
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7.
In order to determine the relative activity of four metals, each metal was placed in the salt solutions of the other metals and observed for signs of a reaction. The results are displayed in the table. Note that R = reaction occurred; NR = no sign of a reaction; – = not tested
Metal 1 Salt solution of Metal 1 Salt solution of Metal 2 Salt solution of Metal 3 Salt solution of Metal 4 – R NR R
Metal 2 NR – NR R
Metal 3 R R – R
Metal 4 NR NR NR –
What is the relative activity of the four metals as determined by these results? most active metal least active metal (A) (B) (C) (D) 3142 2143 3124 4213
8.
Which of the following is a Bronsted- Lowry acid – base reaction? (i) (ii) (iii) (iv) CO2(g) + H2O(l) HCO3– (aq) + H+ (aq)
H2SO4(l) + H2O(l) HSO4–(aq) + H3O +(aq) CaO(s) + CO2 (g) CaCO3(s) NH3(g) + HCl (g) NH4Cl (s) all the reactions (i) and (iii) only (ii) and (iv) only (iii) and (iv) only
(A) (B) (C) (D)
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9
Given the following ionization/dissociation of hypothetical acids and bases in water: (i) (ii) (iii) (iv) HL(g) + H2O(l) H3O+(aq) + L– (aq) MOH(s)
water
M+ (aq) + OH– (aq) Z–(aq) + H3O+(aq)
HZ(g) + H2O(l) H2D–(aq) + H2O(l)
HD2– (aq) + H3O+ (aq)
Which combinations would produce a buffer? (A) (B) (C) (D) NaL – HL and MOH – NaCl NaZ – HL and MOH – NaCl NaH2D – Na2HD and NaZ – HZ NaH2D – Na2HD and MCl – NaOH
10.
What is the correct burette reading in mL?
(A) (B) (C) (D)
21.10 21.30 21.60 22.40
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11.
The concentration of chloride ion in river water was determined by titration with AgNO 3 solution using a suitable indicator. 25.00 mL samples of river water were titrated with 1.034 x 10–2 mol L–1 AgNO3. The average titre was 22.60 mL. What is the concentration of the chloride ion in the river water? (A) (B) (C) (D) 9.348 x 10-3 mol L-1 331 ppm 3.31 x 10 -2 % 0.01148 mol L-1
12.
How many structural isomers can the compound with the molecular formula, C2H3Cl2F have? (A) (B) (C) (D) 1 2 3 4
13.
What is the systematic name of the following compound?
H Br C F C F Cl C H C Cl
Br C
Br H
Br H
(A) (B) (C) (D)
1,1,2,4– tribromo–4,5-dichloro–3,3–fluropentane 1,2– dichloro–2,4,55-tetrabromo– 3,3–difluoropentane 3,3– difluoro-4,5– dichloro–1,1,2,4–tetrabromopentane 1,1,2,4– tetrabromo-4,5–dichloro–3,3–difluoropentane
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14.
Ozone exhibits greater reactivity than the oxygen molecule. Which statement best explains this? (A) (B) Ozone has a bent structure which makes it more polar than oxygen Ozone has three oxygen atoms so it is a stronger oxidizing agent than oxygen which has two atoms. Ozone has a higher molecular mass hence dispersion forces are greater. Ozone has a single covalent bond which is more easily broken than the double covalent bond in oxygen.
(C) (D)
15.
What are the volumes in litres of 1 mole of helium gas and 1 mole of nitrogen gas respectively at 25 oC and 100 kPa ? (A) (B) (C) (D) 12.40 L and 24.79 L 24.79 L and 24.79 L 4.0 L and 28.0 L 22.71 L and 22.71 L
16.
Which of the following changes will always shift equilibrium to the left ? 2HI(g) (A) (B) (C) (D) H2(g) adding a catalyst increasing pressure increasing temperature adding more reactant + I2(g) ∆H = – 52 kJ mol-1
17.
In which of the following alternatives are the compounds listed in order of increasing boiling point ? (A) (B) (C) (D) butane, pentanoic acid, propanol propanol, pentanoic acid, butane butane, propanol, pentanoic acid pentanoic acid, pentanol, butane page 8 of 26
JRAHS TRIAL HSC Exam Chemistry 2011
18
20 mL of 0.08 mol L–1 HCl is mixed with 30 mL of a 0.05 mol L–1 NaOH. What is the pH of the resultant solution ? (A) (B) (C) (D) 2.7 4.0 7.0 8.3
19
Which of the following would be a possible industrial source of sulfur dioxide? (A) (B) (C) (D) volcanic eruptions smelting of metal ores photochemical smog electrolysis of sodium chloride
20
. What is the IUPAC name of the following compound ?
H H H H C H H C H H C H H C C H C H
OH H
(A) (B) (C) (D)
1–methyl–2–pentanol 3–hexanol 4– hexanol 5–methyl–4–pentanol
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Student Number ……………………………. Section I Part A Multiple Choice Answer Sheet Mark -----/20
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13 14. 15. 16. 17. 18. 19. 20.
A A A A A A A A A A A A A A A A A A A A
B B B B B B B B B B B B B B B B B B B B
C C C C C C C C C C C C C C C C C C C C
D D D D D D D D D D D D D D D D D D D D
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Student Number ……………….. Part B 55 marks Attempt questions 21 – 33 Allow about 1 hour and 40 minutes for this part Answer the questions in the spaces provided. These spaces provide guidance for the expected length of response Show all relevant working in questions involving calculations. Question 21 (5 marks) Marks
Section 1 (continued)
Ethanol may be formed in a variety of ways using both renewable and non-renewable resources. Ethanol is considered a very important chemical as it has many uses in our society. (a) Describe how ethanol may be prepared from renewable and non-renewable resources. Include relevant equations and state any reaction conditions required. ......................................................................... ............................................................... .......... ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... ........… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …. (b) Explain why ethanol is used as a common solvent for a wide range of chemicals. ............................................................... ........... ............................................................... ........... .......................................................................... ............................................................... ........... .......................................................................... ............................................................... ........... ................................................................. .......… ........................................................................…
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3
2
Question 22 (4 marks) Polymers have revolutionised the way society uses and forms materials. Compare the processes of addition and condensation polymerization using examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………….. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ……………. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………….. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ……………
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Question 23 (6 marks) Galvanic cells were used to form the first type of batteries. (a) In terms of structure and chemistry, compare the galvanic cell that you investigated in the laboratory with either a dry cell or lead-acid cell. ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... .......... ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... .......... ................................................................ ......... ......................................................................... Demonstrate how you would theoretically calculate the standard cell potential (Eø) for the galvanic cell that you investigated in the laboratory.
Marks
5
(b)
1
......................................................................... ............................................................... ..........
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Marks
Question 24 (4 marks) Radioisotopes are important products of nuclear chemistry.
(a)
Describe the use of an identified radioisotope in industry. ......................................................................... ............................................................... .......... ......................................................................... ............................................................... ..........
2
(b)
Outline how the radioisotope identified in (a) is produced. ............................................................... .......... ......................................................................... ............................................................... .......... ............................................................... ..........
2
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Marks
Question 25 (5 marks) A first-hand investigation was carried out to measure the volume of gas produced when 200 mL of hydrochloric acid solution was added to various pieces of zinc. The volume of gas produced was recorded at 25 oC and 100 kPa as shown in the table below : Mass of Zinc (g) 0.12 0.33 0.56 0.83 0.96 1.22 1.64 1.93 (a) Volume of Gas (mL) 45 125 115 315 365 380 380 380 3
Plot a line graph of the results in the grid below.
Question 25 continues on next page
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Marks
(b)
Calculate the theoretical volume of gas produced at 25 oC and 100 kPa by the reaction of 0.75 g zinc with 200 mL of the acid. …………………………………………………………………………………………………… ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. …………………………………………………………………………………………………….
2
Question 26 (3 marks)
pH = 3.38
pH = 2.56
pH = 2.00
0.01 mol L-1 Acetic acid
0.01 mol L-1 Citric acid
0.01 mol L-1 Hydrochloric acid
Explain the difference in pH between the three acids in the diagram. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. ………………………………………………………………………………………………………… …………………………………………………………………………………………………………
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3
Marks
Question 27 (3 marks)
(a)
Identify the common catalyst used in esterification reactions. ………………………………………………………………………………………………..
1
(b)
Outline the role of refluxing in the esterification process. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………………
2
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Question 28 (3 marks) Read the information provided in the fact file about environmental chemists and then answer the question. You may use any other information in addition to the fact file information.
FACT FILE: WORK DESCRIPTION ► An environmental chemist may focus on collecting and analyzing samples, developing remediation programs, changing production processes to yield a more environmentally friendly product, providing expert advice on safety and emergency response, or dealing with government regulations and compliance issues. WORKING CONDITIONS ► Work is often done in an indoor lab environment. However, when studying chemicals in the environment, a riverbed or stream may become the lab. Some companies have sophisticated indoor ecosystems in which they test their products. Others collect data outdoors and kilometres away from their own production sites. PERSONAL CHARACTERISTICS ► Because environmental chemistry is so interdisciplinary, it requires excellent interpersonal and communication skills along with the ability to express ideas efficiently to a non scientific audience. The importance of the latter becomes apparent when chemists deal with regulations or with a company’s sales and marketing staff.
Explain why collaboration between chemists is essential if the environmental aspects of the industry are to be considered. ............................................................................................................................................................................ ........................................................................................................................................................................... ........................................................................................................................................................................... ........................................................................................................................................................................... .......................................................................................................................................................................... .......................................................................................................................................................................... .......................................................................................................................................................................... ..........................................................................................................................................................................
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Marks
Question 29 (7 marks) A student carried out an investigation to analyse lawn fertiliser. The student weighed out 1.00 g of fertiliser containing 24.0 % sulfur (S) and dissolved it in water. 100 mL of 0.20 mol L1 barium chloride solution was then added and a precipitate formed. Calculate the theoretical percentage by mass of sulfate (SO 42–) in the fertiliser. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ………………………………………………………………………………………………..
(a)
3
(b)
Complete the table to explain the possible cause(s) of deviation of the result from the expected value. Lower value Higher value
4
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Marks
Question 30 (6 marks) Aluminium has often been linked to Alzheimer’s disease whose symptom is rapid memory loss. Common drinks, such as tea may contain higher than normal levels of aluminium ions: Considering that tea is such a popular drink, a group of students decided to analyse, the level of aluminium in black tea samples by AAS when given the chance to use the instrument in a nearby university. They weighed out 10.00 g of tea and made an infusion with 500.0 mL of demineralised water. They allowed 2 minutes for the infusion time. At the same time they prepared standard aluminium solutions ranging from 1.00 ppm to 6.00 ppm. They passed replicate samples of the tea infusion and the standards through the AAS instrument and obtained the following results: Data table Sample
Concentration (ppm) 1.25 2.53 3.68 4.67 5.43 unknown unknown unknown unknown
Absorbance
Standard 1 Standard 2 Standard 3 Standard 4 Standard 5 Tea infusion1 Tea infusion 2 Tea infusion 3 Tea infusion 4
0.1002 0.2111 0.3205 0.4504 0.5216 0.3565 0.3566 0.3565 0.3566
(a)
Assess the reliability of the analysis of the tea infusions of unknown concentrations.
1
............................................................................................................................................................ ............................................................................................................................................................ ............................................................................................................................................................
Question 30 continues on next page…
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Marks
(b)
The diagram below shows a graph of the results obtained by the students.
Use the graph and the data table to determine the average concentration of aluminium in ppm in the tea infusion.
1
.......................................................................................................................................................... ..........................................................................................................................................................
Question 30 continues on next page…
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Marks
(c)
2.0 g of black tea is required to make a 220 mL cup of tea and the daily tolerable limit for aluminium in tea is 7.0 mg/kg body weight. How many cups of tea a day can a 55 kg person drink without exceeding the tolerable limit of aluminium?
4
.......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... .......................................................................................................................................................... ..........................................................................................................................................................
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Question 31 (6 marks) Discuss how manufactured products have had a damaging impact on the composition of the atmosphere and evaluate the measures being taken to decrease the damage.
..................................................................................................................................................................... ...................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... .....................................................................................................................................................................
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Question 32 (3 marks) A water sample from a waterway was found to have high levels of turbidity and dissolved solids together with increased biochemical oxygen demand. Assses the ability of this waterway to sustain aquatic life.
3
....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... .......................................................................................................................................................................
Test continues next page..
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Section II
25 marks Attempt question 33 Allow about 45 minutes for this section Answer the question in a writing booklet. Show all relevant working in questions involving calculations.
Marks
(a)
The Solvay Process is used to produce sodium carbonate. One step in the process involves the decomposition, by heat, of sodium hydrogen carbonate. (i) (ii) Give an equation for this reaction. If 10 100 tonnes of sodium hydrogen carbonate is heated, what volume of gas will be produced at 25 oC? What happens to the gas produced in this step of the Solvay Process? 1
3 1
(iii)
(b)
The flowchart shows the production and distribution of sulfuric acid.
A extraction of raw materials
B production of sulfuric acid
C transportation of sulfuric acid
(i) (ii) (c)
Identify one safety or environmental issue associated with A, B and C. Describe the precautions taken to avoid the consequence of each issue identified. 6
An impurity in natural gas is hydrogen sulfide or rotten egg gas. This gas can be removed from natural gas by the following process. 2H2S (g) + SO2 (g) (i) (ii) 3S (s) + 2H2O (g) ∆H = – 145 kJ mol-1 1
Give the equilibrium expression for this reaction. Calculate the equilibrium constant when 2.00 mol of H2S and 2.00 mol of SO2 react in a 1.00 L vessel at 100 oC to give 1.00 mol of water vapour under equilibrium conditions. What conditions of temperature and pressure would favour the removal of hydrogen sulfide gas? Explain these conditions in terms of Le Chatelier’s principle. Question 33 continues next page..
2
(iii)
4
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Marks
(d)
You performed a first-hand investigation to identify the products of electrolysis of aqueous sodium chloride. Identify the product at either the cathode or the anode and describe the test you performed to identify that product.
3
(e)
Distinguish between cationic and non-ionic detergents in terms of their chemical composition and usage.
4
End of Test
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Mark / 100
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 a Periodic Table are provided. Write your Student Number at the top of this page and those of pages 10 and 11.
Total Marks – 100 Section I Pages 2 – 24
Confidential Keep Secure
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 – 32 •Allow about 1 hour and 40 minutes for this part Pages 25 – 26
Section II 25 marks
•Attempt Question 33 •Allow about 45 minutes for this section …show more content…
JRAHS TRIAL HSC Exam Chemistry 2011
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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 on page .....
Mark your answers on the ANSWER grid on page 10. ________________________________________________________________________________
JRAHS TRIAL HSC Exam Chemistry 2011
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Part A Multiple Choice Use the multiple – choice answer sheet for Questions 1 – 20 . 1. Which of the following chemicals would decolourise bromine water the quickest in the presence of UV light? (A) (B) (C) (D) Concentrated H2SO4 Cyclohexane 1-hexene 1-hexanol
2.
What products would result from the catalytic cracking of a 15-carbon alkane? (A) (B) (C) (D) One alkane and one alkene One alkanoic acid and one alkanol Two alkanes Two alkenes
3.
The molar heat of combustion of ethanol is 1367 kJ mol-1. A 2.510 g sample of ethanol was combusted in heating a certain mass of water from 25 oC to 45oC. 80% of the heat released was absorbed by the water. What was the quantity of water heated? (A) (B) (C) (D) 712.7 g 713.8 g 890.9 g 892.2 g
JRAHS TRIAL HSC Exam Chemistry 2011
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4.
A sample was tested for its approximate pH using several indicators. The results are given in the table. Indicator bromothymol blue litmus methyl orange phenolphthalein What is the most accurate estimate for the pH of the sample? (A) (B) (C) (D) Between 6.0 and 6.3 7.0 Between 7.5 and 8.0 Between 9.0 and 14.0 Colour of indicator in sample blue blue yellow colourless
5.
Why is radon-226 a radioactive isotope? (A) (B) (C) (D) Its mass number is greater than 83. It has more neutrons than protons. The ratio of neutrons to protons is not 1:1. The ratio of neutrons to protons is too low.
6.
The half-equations for the vanadium redox cell are given below. VO2+ (aq) + 2H+ + e- VO2+ (aq) + H2O (l) V2+ (aq) V3+ (aq) + eWhat is the change in the oxidation state of vanadium for the reduction half-equation in this cell? (A) (B) (C) (D) 2+ to 0 3+ to 2+ 2+ to 3+ 5+ to 4+
JRAHS TRIAL HSC Exam Chemistry 2011
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7.
In order to determine the relative activity of four metals, each metal was placed in the salt solutions of the other metals and observed for signs of a reaction. The results are displayed in the table. Note that R = reaction occurred; NR = no sign of a reaction; – = not tested
Metal 1 Salt solution of Metal 1 Salt solution of Metal 2 Salt solution of Metal 3 Salt solution of Metal 4 – R NR R
Metal 2 NR – NR R
Metal 3 R R – R
Metal 4 NR NR NR –
What is the relative activity of the four metals as determined by these results? most active metal least active metal (A) (B) (C) (D) 3142 2143 3124 4213
8.
Which of the following is a Bronsted- Lowry acid – base reaction? (i) (ii) (iii) (iv) CO2(g) + H2O(l) HCO3– (aq) + H+ (aq)
H2SO4(l) + H2O(l) HSO4–(aq) + H3O +(aq) CaO(s) + CO2 (g) CaCO3(s) NH3(g) + HCl (g) NH4Cl (s) all the reactions (i) and (iii) only (ii) and (iv) only (iii) and (iv) only
(A) (B) (C) (D)
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9
Given the following ionization/dissociation of hypothetical acids and bases in water: (i) (ii) (iii) (iv) HL(g) + H2O(l) H3O+(aq) + L– (aq) MOH(s)
water
M+ (aq) + OH– (aq) Z–(aq) + H3O+(aq)
HZ(g) + H2O(l) H2D–(aq) + H2O(l)
HD2– (aq) + H3O+ (aq)
Which combinations would produce a buffer? (A) (B) (C) (D) NaL – HL and MOH – NaCl NaZ – HL and MOH – NaCl NaH2D – Na2HD and NaZ – HZ NaH2D – Na2HD and MCl – NaOH
10.
What is the correct burette reading in mL?
(A) (B) (C) (D)
21.10 21.30 21.60 22.40
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11.
The concentration of chloride ion in river water was determined by titration with AgNO 3 solution using a suitable indicator. 25.00 mL samples of river water were titrated with 1.034 x 10–2 mol L–1 AgNO3. The average titre was 22.60 mL. What is the concentration of the chloride ion in the river water? (A) (B) (C) (D) 9.348 x 10-3 mol L-1 331 ppm 3.31 x 10 -2 % 0.01148 mol L-1
12.
How many structural isomers can the compound with the molecular formula, C2H3Cl2F have? (A) (B) (C) (D) 1 2 3 4
13.
What is the systematic name of the following compound?
H Br C F C F Cl C H C Cl
Br C
Br H
Br H
(A) (B) (C) (D)
1,1,2,4– tribromo–4,5-dichloro–3,3–fluropentane 1,2– dichloro–2,4,55-tetrabromo– 3,3–difluoropentane 3,3– difluoro-4,5– dichloro–1,1,2,4–tetrabromopentane 1,1,2,4– tetrabromo-4,5–dichloro–3,3–difluoropentane
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14.
Ozone exhibits greater reactivity than the oxygen molecule. Which statement best explains this? (A) (B) Ozone has a bent structure which makes it more polar than oxygen Ozone has three oxygen atoms so it is a stronger oxidizing agent than oxygen which has two atoms. Ozone has a higher molecular mass hence dispersion forces are greater. Ozone has a single covalent bond which is more easily broken than the double covalent bond in oxygen.
(C) (D)
15.
What are the volumes in litres of 1 mole of helium gas and 1 mole of nitrogen gas respectively at 25 oC and 100 kPa ? (A) (B) (C) (D) 12.40 L and 24.79 L 24.79 L and 24.79 L 4.0 L and 28.0 L 22.71 L and 22.71 L
16.
Which of the following changes will always shift equilibrium to the left ? 2HI(g) (A) (B) (C) (D) H2(g) adding a catalyst increasing pressure increasing temperature adding more reactant + I2(g) ∆H = – 52 kJ mol-1
17.
In which of the following alternatives are the compounds listed in order of increasing boiling point ? (A) (B) (C) (D) butane, pentanoic acid, propanol propanol, pentanoic acid, butane butane, propanol, pentanoic acid pentanoic acid, pentanol, butane page 8 of 26
JRAHS TRIAL HSC Exam Chemistry 2011
18
20 mL of 0.08 mol L–1 HCl is mixed with 30 mL of a 0.05 mol L–1 NaOH. What is the pH of the resultant solution ? (A) (B) (C) (D) 2.7 4.0 7.0 8.3
19
Which of the following would be a possible industrial source of sulfur dioxide? (A) (B) (C) (D) volcanic eruptions smelting of metal ores photochemical smog electrolysis of sodium chloride
20
. What is the IUPAC name of the following compound ?
H H H H C H H C H H C H H C C H C H
OH H
(A) (B) (C) (D)
1–methyl–2–pentanol 3–hexanol 4– hexanol 5–methyl–4–pentanol
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Student Number ……………………………. Section I Part A Multiple Choice Answer Sheet Mark -----/20
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13 14. 15. 16. 17. 18. 19. 20.
A A A A A A A A A A A A A A A A A A A A
B B B B B B B B B B B B B B B B B B B B
C C C C C C C C C C C C C C C C C C C C
D D D D D D D D D D D D D D D D D D D D
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Student Number ……………….. Part B 55 marks Attempt questions 21 – 33 Allow about 1 hour and 40 minutes for this part Answer the questions in the spaces provided. These spaces provide guidance for the expected length of response Show all relevant working in questions involving calculations. Question 21 (5 marks) Marks
Section 1 (continued)
Ethanol may be formed in a variety of ways using both renewable and non-renewable resources. Ethanol is considered a very important chemical as it has many uses in our society. (a) Describe how ethanol may be prepared from renewable and non-renewable resources. Include relevant equations and state any reaction conditions required. ......................................................................... ............................................................... .......... ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... ........… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …. (b) Explain why ethanol is used as a common solvent for a wide range of chemicals. ............................................................... ........... ............................................................... ........... .......................................................................... ............................................................... ........... .......................................................................... ............................................................... ........... ................................................................. .......… ........................................................................…
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3
2
Question 22 (4 marks) Polymers have revolutionised the way society uses and forms materials. Compare the processes of addition and condensation polymerization using examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………….. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ……………. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………….. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . …………… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ……………
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Question 23 (6 marks) Galvanic cells were used to form the first type of batteries. (a) In terms of structure and chemistry, compare the galvanic cell that you investigated in the laboratory with either a dry cell or lead-acid cell. ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... .......... ............................................................... .......... ......................................................................... ............................................................... .......... ......................................................................... ............................................................... .......... ................................................................ ......... ......................................................................... Demonstrate how you would theoretically calculate the standard cell potential (Eø) for the galvanic cell that you investigated in the laboratory.
Marks
5
(b)
1
......................................................................... ............................................................... ..........
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Marks
Question 24 (4 marks) Radioisotopes are important products of nuclear chemistry.
(a)
Describe the use of an identified radioisotope in industry. ......................................................................... ............................................................... .......... ......................................................................... ............................................................... ..........
2
(b)
Outline how the radioisotope identified in (a) is produced. ............................................................... .......... ......................................................................... ............................................................... .......... ............................................................... ..........
2
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Marks
Question 25 (5 marks) A first-hand investigation was carried out to measure the volume of gas produced when 200 mL of hydrochloric acid solution was added to various pieces of zinc. The volume of gas produced was recorded at 25 oC and 100 kPa as shown in the table below : Mass of Zinc (g) 0.12 0.33 0.56 0.83 0.96 1.22 1.64 1.93 (a) Volume of Gas (mL) 45 125 115 315 365 380 380 380 3
Plot a line graph of the results in the grid below.
Question 25 continues on next page
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Marks
(b)
Calculate the theoretical volume of gas produced at 25 oC and 100 kPa by the reaction of 0.75 g zinc with 200 mL of the acid. …………………………………………………………………………………………………… ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. …………………………………………………………………………………………………….
2
Question 26 (3 marks)
pH = 3.38
pH = 2.56
pH = 2.00
0.01 mol L-1 Acetic acid
0.01 mol L-1 Citric acid
0.01 mol L-1 Hydrochloric acid
Explain the difference in pH between the three acids in the diagram. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. ………………………………………………………………………………………………………… …………………………………………………………………………………………………………
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3
Marks
Question 27 (3 marks)
(a)
Identify the common catalyst used in esterification reactions. ………………………………………………………………………………………………..
1
(b)
Outline the role of refluxing in the esterification process. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………………
2
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Question 28 (3 marks) Read the information provided in the fact file about environmental chemists and then answer the question. You may use any other information in addition to the fact file information.
FACT FILE: WORK DESCRIPTION ► An environmental chemist may focus on collecting and analyzing samples, developing remediation programs, changing production processes to yield a more environmentally friendly product, providing expert advice on safety and emergency response, or dealing with government regulations and compliance issues. WORKING CONDITIONS ► Work is often done in an indoor lab environment. However, when studying chemicals in the environment, a riverbed or stream may become the lab. Some companies have sophisticated indoor ecosystems in which they test their products. Others collect data outdoors and kilometres away from their own production sites. PERSONAL CHARACTERISTICS ► Because environmental chemistry is so interdisciplinary, it requires excellent interpersonal and communication skills along with the ability to express ideas efficiently to a non scientific audience. The importance of the latter becomes apparent when chemists deal with regulations or with a company’s sales and marketing staff.
Explain why collaboration between chemists is essential if the environmental aspects of the industry are to be considered. ............................................................................................................................................................................ ........................................................................................................................................................................... ........................................................................................................................................................................... ........................................................................................................................................................................... .......................................................................................................................................................................... .......................................................................................................................................................................... .......................................................................................................................................................................... ..........................................................................................................................................................................
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Marks
Question 29 (7 marks) A student carried out an investigation to analyse lawn fertiliser. The student weighed out 1.00 g of fertiliser containing 24.0 % sulfur (S) and dissolved it in water. 100 mL of 0.20 mol L1 barium chloride solution was then added and a precipitate formed. Calculate the theoretical percentage by mass of sulfate (SO 42–) in the fertiliser. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ………………………………………………………………………………………………..
(a)
3
(b)
Complete the table to explain the possible cause(s) of deviation of the result from the expected value. Lower value Higher value
4
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Marks
Question 30 (6 marks) Aluminium has often been linked to Alzheimer’s disease whose symptom is rapid memory loss. Common drinks, such as tea may contain higher than normal levels of aluminium ions: Considering that tea is such a popular drink, a group of students decided to analyse, the level of aluminium in black tea samples by AAS when given the chance to use the instrument in a nearby university. They weighed out 10.00 g of tea and made an infusion with 500.0 mL of demineralised water. They allowed 2 minutes for the infusion time. At the same time they prepared standard aluminium solutions ranging from 1.00 ppm to 6.00 ppm. They passed replicate samples of the tea infusion and the standards through the AAS instrument and obtained the following results: Data table Sample
Concentration (ppm) 1.25 2.53 3.68 4.67 5.43 unknown unknown unknown unknown
Absorbance
Standard 1 Standard 2 Standard 3 Standard 4 Standard 5 Tea infusion1 Tea infusion 2 Tea infusion 3 Tea infusion 4
0.1002 0.2111 0.3205 0.4504 0.5216 0.3565 0.3566 0.3565 0.3566
(a)
Assess the reliability of the analysis of the tea infusions of unknown concentrations.
1
............................................................................................................................................................ ............................................................................................................................................................ ............................................................................................................................................................
Question 30 continues on next page…
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Marks
(b)
The diagram below shows a graph of the results obtained by the students.
Use the graph and the data table to determine the average concentration of aluminium in ppm in the tea infusion.
1
.......................................................................................................................................................... ..........................................................................................................................................................
Question 30 continues on next page…
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Marks
(c)
2.0 g of black tea is required to make a 220 mL cup of tea and the daily tolerable limit for aluminium in tea is 7.0 mg/kg body weight. How many cups of tea a day can a 55 kg person drink without exceeding the tolerable limit of aluminium?
4
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Question 31 (6 marks) Discuss how manufactured products have had a damaging impact on the composition of the atmosphere and evaluate the measures being taken to decrease the damage.
..................................................................................................................................................................... ...................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... .....................................................................................................................................................................
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Question 32 (3 marks) A water sample from a waterway was found to have high levels of turbidity and dissolved solids together with increased biochemical oxygen demand. Assses the ability of this waterway to sustain aquatic life.
3
....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... ....................................................................................................................................................................... .......................................................................................................................................................................
Test continues next page..
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Section II
25 marks Attempt question 33 Allow about 45 minutes for this section Answer the question in a writing booklet. Show all relevant working in questions involving calculations.
Marks
(a)
The Solvay Process is used to produce sodium carbonate. One step in the process involves the decomposition, by heat, of sodium hydrogen carbonate. (i) (ii) Give an equation for this reaction. If 10 100 tonnes of sodium hydrogen carbonate is heated, what volume of gas will be produced at 25 oC? What happens to the gas produced in this step of the Solvay Process? 1
3 1
(iii)
(b)
The flowchart shows the production and distribution of sulfuric acid.
A extraction of raw materials
B production of sulfuric acid
C transportation of sulfuric acid
(i) (ii) (c)
Identify one safety or environmental issue associated with A, B and C. Describe the precautions taken to avoid the consequence of each issue identified. 6
An impurity in natural gas is hydrogen sulfide or rotten egg gas. This gas can be removed from natural gas by the following process. 2H2S (g) + SO2 (g) (i) (ii) 3S (s) + 2H2O (g) ∆H = – 145 kJ mol-1 1
Give the equilibrium expression for this reaction. Calculate the equilibrium constant when 2.00 mol of H2S and 2.00 mol of SO2 react in a 1.00 L vessel at 100 oC to give 1.00 mol of water vapour under equilibrium conditions. What conditions of temperature and pressure would favour the removal of hydrogen sulfide gas? Explain these conditions in terms of Le Chatelier’s principle. Question 33 continues next page..
2
(iii)
4
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Marks
(d)
You performed a first-hand investigation to identify the products of electrolysis of aqueous sodium chloride. Identify the product at either the cathode or the anode and describe the test you performed to identify that product.
3
(e)
Distinguish between cationic and non-ionic detergents in terms of their chemical composition and usage.
4
End of Test
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