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Chemistry
General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen.
Black pen is preferred • Draw diagrams using pencil • Board-approved calculators may be
used
Total marks – 100 Section I Pages 2–19 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 21–30 • Allow about 1 hour and 40 minutes for this part Section II Pages 21–31 25 marks • Attempt ONE question from Questions 31–35 • Allow about 45 minutes for this section
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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 for Questions 1-20.
1 Excess barium nitrate solution is added to 600 mL of 0.100 mol L–1 sodium sulfate. What is the mass of the solid formed? (A) 0.06g
(B) 4.08g
(C) 14.00g
(D) 16.01g
2 What is the IUPAC name of this alcohol?
(A) Propan-1-ol
(B) Hexan-1-ol
(C) Ethan-1-ol
(D) Butan-1-ol
3 Cellulose is a naturally occurring polymer. It uses what form of polymerisation
to form long chains used in plant material? (A) Addition polymerisation
(B) Condensation polymerisation
(C) Propagation polymerisation
(D) Termination polymerisation
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4 Which of the following is the correct formula for the reaction between
hydrogen and nitrogen to form ammonia? (A) N2 + H2 ↔ NH3 ΔH= -92.4 kJ mol-1
(B) N2 + 3H2 ↔ NH3 ΔH= +92.4 kJ mol-1
(C) N2 + 3H2 ↔ 2NH3 ΔH= -92.4 kJ mol-1
(D) N2 + 3H2 ↔ 2NH3 ΔH= -92.4 J mol-1
5 What is the hydrogen ion concentration of a solution labelled "Solution A",
whose pH is 5.60?
(A) 2.51x10-6 M.
(B) 4.61x10-6 M.
(C) 5.60x10-6 M.
(D) 3.65x10-6 M
6 Which of the following measures of water quality is able to be determined by
sight alone? (A) Concentrations of common ions
(B) Hardness
(C) Turbidity
(D) Acidity
7 Why is ethanol considered a renewable resource?
(A) It is derived from crude oil which will not run out.
(B) It can be made from plant material which can regrow.
(C) It burns cleanly in air, from less incomplete combustion.
(D) It uses more land for production than crude oil.
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8 Le Chatelier’s principle is defined as:
(A) If a factor is put on a system, the system will adjust the equilibrium to counteract the change.
(B) The heat given off by a solution is equal to the change in energy of that system.
(C) A system will only continue in one direction. (D) A method of predicting the behaviour of a gas in a closed chamber.
9 Sulfur dioxide is a naturally produced molecule mainly formed from:
(A) Lightning
(B) Volcanic activity
(C) Industrial Revolution
(D) Exhaust fumes from cars
10 HCO3 is an amphoteric species as shown by the two equations
HCO3-
(aq) + HCl (aq) ↔ H2CO3 (aq) + Cl- (aq)
HCO3- (aq) + OH- ↔ CO3
2- (aq) + H2O(aq)
Choose the conjugate acid HCO3
- (aq) from the list below.
(A) OH-
(B) HCl
(C) H2O
(D) CO32-
11 Which of the following dissolves in water to form a basic solution?
(A) Potassium citrate
(B) Sodium nitrate
(C) Ammonium chloride
(D) Aluminium sulfate
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12 Methanol can be produced through the reaction of carbon monoxide with hydrogen, as shown below:
CO (g) + 2H2 ↔ CH3OH ΔH = -155 kJ mol-1
Which of the following conditions would increase the equilibrium yield of methanol?
(A) High pressure and temperature
(B) Low pressure and temperature
(C) High pressure and low temperature
(D) Low pressure and high temperature
13 Where on the Periodic Table would you most likely find elements which form basic oxides?
(A) Group 1
(B) Group 6
(C) Period 2
(D) Period 3
14 Which elements on the Periodic Table have radioisotopes?
(A) Only those elements after uranium.
(B) Only the actinides.
(C) Only elements with unstable proton-neutron ratio.
(D) Only metallic elements
15 The pH of 0.0015 mol L-1 nitric acid is closest to:
(A) 2
(B) 3
(C) -2
(D) 1.5
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16 Ozone is found in highest concentrations in the layer of the atmosphere known
as the:
(A) Troposphere
(B) Stratosphere
(C) Mesosphere
(D) Thermosphere
17 Zinc metal can be formed by extracting it from its ore. The first step in this extraction process is to roast the sulfide ore in the air.
2 ZnS (s) + 3O2 → 2ZnO + 2SO2
300kg of zinc sulphide is roasted with air.
The volume of sulfur dioxide released into the atmosphere at 101.3kPa and 298 K is closest to: (A) 130 mL
(B) 75 L
(C) 130 L
(D) 75000 L
18 Which statement corresponds best with Davy's ideas about acids and bases? (A) An acid is a substance that provides H+ ions in aqueous solution.
(B) All acids contain the element hydrogen.
(C) The presence of oxygen in compounds formed from non-metals, causes
acidity.
(D) An acid is a proton donor.
19 Water hardness is used to describe water that contains significant amounts of
specific ions. These ions are:
(A) Na+ and Cl- ions
(B) NH4+ and OH- ions
(C) Hg2+ and Pb2+ ions
(D) Mg2+ and Ca2+ ions
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20 The concentration of ozone in the troposphere is 0.000002% (v/v). What is this
concentration in parts per million (ppm)? (A) 0.0002
(B) 0.002
(C) 0.02
(D) 20
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2017 MOCK HSC EXAMINATION
Chemistry
Section I (continued) Part B – 55 marks Attempt Questions 21–30 Allow about 1 hour and 40 minutes for this section Answer the questions in the spaces provided. These spaces provide guidance for the expected length of response. Extra writing space is provided on pages 18 and 19. If you use this space, clearly indicate which question you are answering. Write your Centre Number and Student Number at the top of this page.
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Question 21 (4 marks) The dehydration of ethanol to ethylene requires a catalyst to occur. (a) State the catalyst used in the dehydration of ethanol 1
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(b) Explain the need for a catalyst in this reaction 3
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Question 22 (3 marks)
A student is unsure of the differences between the Arrhenius theory of acids and the Bronsted-Lowry theory of acids. Compare and contrast the two theories. 3
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Question 23 (4 marks) As a result of Avogadro’s work, it was understood that one mole of any gas would occupy the same volume at standard conditions of temperature and pressure.
(a) State the name of this law ……………………………………………………………………………………
(b) When magnesium reacts completely with sulfuric acid, hydrogen gas is
formed. Calculate the mass of magnesium needed to produce 2.5 L of hydrogen at 25°C and 1 atm pressure.
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Question 24 (6 marks)
Chlorofluorocarbons pose a significant problem to the atmosphere due to their interactions with ozone.
(a) Identify the origins of chlorofluorocarbons in the atmosphere. 1
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(b) Describe why ozone becomes depleted in the presence of CFC’s and halons in the atmosphere, ensuring to include the equations involved. 4 ……………………………………………………………………………………
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(c) The following graph shows the relationship between the Montreal Protocol and the concentration of CFCs and their replacements over the past 40 years.
Suggest a reason for the difference in emissions versus concentration in CFCs (darker lines) and HFCs (lighter lines). 2 ……………………………………………………………………………………
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Question 25 (6 marks) Carbon dioxide is a metabolic product which dissociates when in water.
(a) Identify the equilibrium reaction in this process and whether the reaction is exothermic or endothermic.
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(b) Describe how Le Chatelier’s principle will affect this system as it tries to reach
equilibrium making sure to identify any factors involved. 4
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Question 26 (5 marks) In order to form ethylene, thermal cracking is used to take ethane gas to ethylene. Below is an image of the catalytic cracking process.
(a) Explain why thermal cracking is also used in this process. 2 ………………………………………………………………………………….
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(b) Outline the steps involved in creating polyethylene from the monomer, ethylene. 3
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Question 27 (6 marks) Acid rain occurs when by-products of combustion dissolve in water and mix with oxygen in the atmosphere.
(a) Construct a flow chart to show how acid rain is formed. 4
(b) Explain one effect that acid rain can have. 2
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Question 28 (5 marks) Analyse the need for collaboration between chemists, in the context of monitoring environmental pollution. Make sure to include the main chemical principle that each type of chemist would use.
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Question 29 (8 marks)
The diagram above represents the Haber process which is a method used to create ammonia from its components.
(a) Briefly describe why the Haber process was invented 2
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(b) Name two examples of uses of ammonia 2
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(c) List the steps involved, including any variables that need to be managed or monitored in the Haber process.
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Question 30 (8 marks)
In your studies, you will have researched the development into a biopolymer. Evaluate the use of biopolymers, in regard to the following:
- How does the specific enzyme or organism that you researched is used to synthesise the material?
- What advantages does the biopolymer have over traditional materials? - Any disadvantages that the biopolymer may have - Potential uses for the biopolymer that you researched
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2017 MOCK HSC EXAMINATION
Chemistry
Section II
25 marks Attempt ONE question from Questions 31–35 Allow about 45 minutes for this section
Answer the question in the Section II Writing Booklet. Extra writing booklets are
available.
Pages
Question 31 Industrial Chemistry ............................................................... 23
Question 32 Shipwrecks, Corrosion and Conservation .............................. 24
Question 33 The Biochemistry of Movement ............................................ 25
Question 34 The Chemistry of Art ............................................................. 26-27
Question 35 Forensic Chemistry ................................................................ 29
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Question 31 – Industrial Chemistry (25 marks)
Electrolysis is an important industrial process.
(c) (i) Define electrolysis.
(ii) Compare the reaction products from the electrolysis of molten sodium chloride and concentrated aqueous sodium chloride.
(d) Carbonyl chloride, COCl2, is a colourless, poisonous gas that is also known as
phosgene. It is needed for the production of insecticides, polyurethane plastics and polycarbonate. It is produced from the exothermic equilibrium reaction of carbon monoxide gas and chlorine gas. When the reaction vessel is cooled below 8°C the phosgene is a liquid.
(i) Write a balanced equation for the formation of phosgene at 4°C
(ii) Explain how industry could maximise the production of phosgene. (e) Explain why sulfuric acid is an important industrial chemical. Include balanced
chemical equations in your answer.
(f)
(i) Name the chemical process used to make soap. (ii) Outline the procedure for making soap in the school laboratory.
(iii) Describe a safety risk associated with the procedure outlined in part (ii), and
suggest a safe work practice to minimise the risk.
(g) Evaluate how environmental issues are addressed in the Solvay process.
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Question 32 — Shipwrecks and Salvage (25 marks) (a) (i) Identify the main metal used to construct ships.
(ii) Although aluminium is a very reactive metal, with a very low reduction
potential, it is used in many structures exposed to oxidising conditions.
Explain why aluminium can be used in this way.
(b) (i) Give an example of a metal commonly used as a sacrificial anode.
(ii) Explain why sacrificial anodes are added to metal-hulled ships.
(c) Describe the effect of adding other elements to iron on the properties and uses of steels.
(d) (i) Define corrosion.
(ii) Outline a procedure that could be used to compare the corrosion rates of different metals or alloys in the school laboratory.
(iii) Describe ways in which accuracy and reliability could be improved in
the procedure described in part (ii).
(e) For ONE specific metal, evaluate the steps that can be used to clean, stabilise and preserve artefacts recovered from shipwrecks.
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Question 33 – The Chemistry of Movement (25 marks)
(a) (i) Name the molecule that stores energy for nearly all metabolic processes.
(ii) Explain how the biologically important part of the molecule in part (i)
provides energy for cellular metabolism. (b) Energy for our bodies to function is provided by the oxidation of fuels. Fats
and glucose are used as fuels. A summary of the oxidation of fats and glucose is shown.
(i) Identify molecule X and state its function.
(ii) Analyse the role of oxidative phosphorylation in energy production
(c) Discuss the use of models in developing an understanding of enzyme function. (d) (i) Define viscosity.
(ii) Outline a procedure that could be used to compare the viscosity of pure glycerol and a glycerol solution.
(iii) Describe ways in which accuracy and reliability could be improved in
the procedure described in part (ii).
(e) The energy requirements for different types of skeletal muscle are met by the interaction of separate energy output systems. Analyse the role and interaction of the energy output systems used by skeletal muscle.
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Question 34 – The Chemistry of Art (25 marks) (a) (i) Identify the mineral source of a pigment.
(ii) Describe the use of a named separation process to obtain a pigment.
(b) A sample of a mineral used as a pigment was subjected to spectroscopic analysis. The spectrum is shown.
(i) Identify the elements in the mineral sample.
(ii) Explain how a line spectrum is produced.
Question 34 continues on next page
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(c) Describe the Bohr model of the atom, and identify ONE merit and ONE limitation of the model
(d) (i) Name a transition element.
(iii) Outline a first-hand investigation to demonstrate the colour changes of a
named transition element as it changes in oxidation state.
(iv) Describe a safety risk associated with the procedure outlined in part (ii), and suggest a safe work practice to minimise the risk.
(e) With reference to TWO pigments, explain how the metallic components produce
colour.
End of Question 34
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Question 35 – Forensic Chemistry (25 marks)
(a) (i) Define organic compounds.
(ii) For ONE class of organic compound, describe a chemical test that
identifies this class.
(b) The table shows fatty acid composition of some common oils and fats.
Fatty acids present (% by weight) Fat or Oil hydrolised
Lauric Palmitic Stearic Oleic Linoleic
Butter 2-3 23-26 10-13 30-40 4-5
Lard <1 28-30 12-18 41-48 6-7
Tallow <1 24-32 14-32 35-38 2-4
Coconut 45-51 4-10 1-5 2-10 0-2
An oily sample was hydrolysed and the fatty acids analysed.
Fatty acids present (% by weight) Lauric Palmitic Stearic Oleic Linoleic
Oil sample
<1 29 28 36 4
(i) Which fat or oil has been identified?
(ii) Explain the solubility in water of fatty acids, in terms of their structure.
(c) Assess the usefulness of mass spectrometry in providing forensic evidence.
(d)
(i) Name ONE technique used by forensic chemists to separate a mixture
of organic compounds.
(iii) In your study of Forensic Chemistry, you performed a first-hand investigation to separate a mixture of organic materials. Outline the procedure.
(iii) Describe ways in which accuracy and reliability could be improved in
the procedure described in part (ii).
(e) Discuss the uses of DNA analysis in forensic chemistry.
END OF PAPER
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