PRACTICE EXAM
2003
YEAR 12 HALF-YEARLY EXAMINATION
NAME __________________________
Chemistry
2 UNIT
GENERAL INSTRUCTIONS
 Reading time - 5 minutes
 Working time - 2 hours
 Write your name on your question and
answer papers.
 Topics examined in this paper are
The Identification and Production of
Materials and sections 1-4 of the
Acidic Environment.
 Attempt ALL questions
 A copy of the Periodic Table Of The
Elements and Data Sheet is supplied.
Please return it at the end of the exam.
 You will require a calculator for this
exam.
 Write all answers in the spaces
provided in the answer booklet using a
blue or black pen. Draw diagrams
using pencil.
 Anything written in the question book
will not be marked.
 If you require scrap paper for working
ask your supervising teacher.
Total Marks = 75
This paper has two parts, Part A and Part B.
Part A
Total marks (15)
Attempt questions 1 - 15
Allow about 25 minutes for this part.
Part B
Total marks (60)
Attempt questions 16 - 27
Allow about 1 hour and 35 minutes for this
part.
Part A Multiple Choice
Select the alternative A, B, C or D that best answers the question.
Fill in the response oval on your answer sheet completely.
1.
The IUPAC systemic name for the structure shown below is
CH3 – CH2 – CH2 – CH – CH – CH3


Br
Cl
(A) 3 - bromo - 2 - chloroheptane
(B) 4 - bromo - 5 - chloroheptane
(C) 3 - bromo - 2 - chlorohexane
(D) 4 - bromo - 5 - chlorohexane
2.
Examine the structural formula of the commercially significant monomer shown below:
The polymer formed from this monomer is
(A)
(B)
(C)
(D)
3.
polychloroethylene
polystyrene
polyvinyl chloride
polypropylene
Ethanol can be converted to ethene. This type of reaction is referred to as
(A) esterification
4.
(C) hydration
(D) dehydration
Chlorine reacts with 1-butene to form 1,2-dichlorobutane. This type of reaction is called
(A) oxidation
5.
(B) polymerisation
(B) hydrolysis
(C) substitution
(D) addition
Cellulose is a biopolymer formed by the
(A) condensation polymerisation of glucose monomers
(B) addition polymerisation of glucose monomers
(C) condensation polymerisation of starch monomers
(D) addition polymerisation of ethene monomers
6.
Which of the following ions will be displaced from solution by iron metal?
(A) Mg2+
7.
(B) Pb2+
(C) Zn2+
(D) Ca2+
Examine the following chemical reaction:
MnO2(S) + 4HCl(aq)  MnCl2(aq) + 2H2O(l) + Cl2(g)
In this reaction the oxidation number of Manganese (Mn) changes from
(A) +4 to +2
(B) +4 to -2
(C) +2 to -2
(D) +2 to -1
8.
In the reaction
Zn(S) + CuSO4(aq)  ZnSO4(aq) + Cu(S)
(A) zinc is reduced
(B) copper ions are the reductant
(C) copper ions are reduced
(D) copper atoms are reduced
9.
Examine the following nuclear reaction:
232
90Th

228
88Ra
+ X
The identity of X in this equation is?
(A) °-1e
10.
(B) °+1e
(C) 42He
(D) gamma radiation
Which of the following is not a method used to produce radioisotopes?
(A) bombarding a nucleus with protons
(B) bombarding a nucleus with neutrons
(C) bombarding a nucleus with the nuclei of other elements
(D) bombarding a nucleus with high intensity light
11.
The pH of human blood needs to stay within the range of 7.35 – 7.45. This range
is mostly maintained by
(A)
(B)
(C)
(D)
12.
the oxygen – carbon dioxide buffer system
the carbonic acid – hydrogen carbonate ion buffer system
the protein haemoglobin accepting hydrogen ions
the movement of sodium and potassium ions into and out of the blood
Which of the following chemicals is an acidic salt?
(A) H2CO3
13.
(B) NH4Cl
(C) NaCl
(D) NaCH3COO
In which of the following reactions is water acting as a Bronsted/Lowry acid?
(A) H3O+(aq) + HPO42-(aq) ⇄ H2O(l) + H2PO4-(aq)
(B) H2O(l) + HCO3-(aq) ⇄ H3O+(aq) + CO32-(aq)
(C) H2O(l) + NH3(g) ⇄ NH4+(aq) + OH-(aq)
(D) H3O+(aq) + HS-(aq) ⇄ H2S(aq) + H2O(l)
14.
A student wrote the correct formula of a chemical as CH3COOH. The correct name
of this chemical is
(A) ethanoic acid
(C) ethanol
15.
(B) methanoic acid
(D) methyl hydrogen carbonate
Which of the following oxides is amphoteric?
(A) Al2O3
(B) Na2O
(C) Cl2O7
(D) MgO
Part B – Longer Response Questions
Answer these questions in the spaces provided in the answer booklet.
Show all relevant working in questions involving calculations.
Question 16.
(6 marks)
Two classes of useful chemical produced from petroleum are the alkanes and
the alkenes.
(a) Write the molecular formula of hexene.
(b) Explain why hexene could be more easily transformed into many different
substances than could hexane.
(c) Hexene and hexane are both liquids at room temperature. Describe a test you
performed in class to distinguish between these two chemicals. In your description
state the result of each test.
(d) Another useful chemical alkene is ethene. Name three substances produced
directly from ethene.
Question 17.
(9 marks)
Ethanol is an important and versatile chemical. It is used as an alcoholic beverage,
an industrial solvent and a fuel.
(a) Draw the structural formula of an ethanol molecule.
(b) Explain in terms of its structure and bonding why ethanol is used as an industrial
solvent.
(c) Today ethanol is being increasingly used as a liquid fuel alternative to petrol.
Evaluate the impact of using liquid fuel alternatives such as ethanol, in society today.
(d) During your study of ethanol you will have carried out an experiment to compare
the heats of combustion of ethanol and at least one other liquid fuel.
(i) Name one other liquid fuel you used for comparison.
(ii) Describe the method you used to compare the heats of combustion of the
two fuels. Include a labelled diagram of your experimental set up.
(iii) State two safety precautions you followed during your experiment.
Question 18.
Current research is being focused on developing low cost packaging materials,
as alternatives to conventional packaging.
Polylactic acid (PLA) is a polymer that is currently being developed. PLA can be
made from lactic acid as shown in the diagram below.
(a) Define the term biopolymer.
(b) Name the organism used to synthesise PLA material.
(c) Explain why PLA is defined as a ‘condensation’ polymer.
(d) PLA polymers are used to make compost bags and food packaging. State two
properties of this polymer that make it particularly suitable for these uses.
(5 marks)
Question 19.
(8 marks)
Examine the drawing of a galvanic cell shown below.
(a) Name the anode in this cell.
(b) Name one electrolyte in this cell.
(c) State one reason why the filter paper is soaked with potassium nitrate.
(d) Construct half-equations for both the reduction and the oxidation reactions in
this cell.
(e) Calculate the theoretical voltage of this cell.
(f) When setting up this cell in class the student made sure the electrodes were
clean and pure. The student was surprised to find that the voltage obtained
was somewhat lower than the theoretical voltage. Suggest two good reasons
that would account for the difference between the theoretical and experimental
values.
Question 20.
(3 marks)
(a) Explain the difference between a stable and a radioactive isotope.
(b) In class you have researched radioisotopes and their uses. Name one
radioisotope used in medicine, describe its use and explain its use in terms
of its chemical properties.
Question 21.
(3 marks)
Purple cabbage indicator contains a pigment that is an excellent acid-base
indicator. The following results were obtained when the extract was tested in some
common household solutions.
Solution tested
Soda water
Tap water
Dilute vinegar
Lemon juice
Baking soda solution
Drain cleaner
Ammonia solution
Indicator colour
Purplish red
Purple
Reddish purple
Red
Blue-green
Yellow
Green
(a) Predict what colour the cabbage indicator will turn in each of the following solutions.
(i) 1 mol L-1 sodium hydroxide solution.
(ii) 1 mol L-1 hydrochloric acid solution.
(b) What piece of equipment could the student use to assess the accuracy of their prediction?
Question 22.
(4 marks)
A student prepared a 5.0 mol L-1 solution of citric acid. Citric acid is really
2-hydroxypropane-1,2,3-tricarboxylic acid. The molecular formula of this
triprotic acid is shown below.
O
H OH


C  C  C 


HO
H
C
O
H
O

C  C

H
OH
OH
(a) Is citric acid a weak or strong acid? Explain.
(b) Is the student’s citric acid solution dilute or concentrated? Explain.
(c) Why is citric acid called a triprotic acid?
Question 23.
(2 marks)
(a) Carbon dioxide CO2, like sulfur dioxide SO2, is described as an acidic oxide.
Explain how this can be true when neither formula contains a H atom.
(b) What general trend in acidity/basicity is shown by oxides across period 3 of
the periodic table?
Question 24.
(4 marks)
The production of sulfur trioxide is an important step in the manufacture of sulfuric
acid.
2SO2(g) + O2(g) ⇄ 2SO3(g)
(a) Explain the significance of the 'double-headed' arrow in the above equation.
(b) Explain how the equilibrium concentration of SO3(g) would be affected by:
(i) increasing the concentration of oxygen gas in the reaction mixture.
(ii) increasing the pressure of the reaction vessel.
(iii) adding a catalyst.
Question 25.
(3 marks)
Sodium hydrogen carbonate (NaHCO3) is an amphoteric compound.
(a) Construct two ionic equations showing the amphoteric nature of the hydrogen
carbonate ion.
(b) Give one conjugate acid-base pair from either of your equations.
Question 26.
'Drano' is a common product used in the home for clearing blocked drains.
A normal bottle of Drano contains 16 grams of sodium hydroxide per 100 mL
of solution.
(a) Calculate the molarity of NaOH in the 'Drano' solution.
(b) Calculate its pH.
(c) Some 'Drano' solution is diluted by a factor of 100 times. What is the 'new'
pH of the diluted solution?
(4 marks)
Question 27.
(3 marks)
A student adds 200 mL of 0.05 mol L-1 HCl to 100 mL of 0.20 mol L-1 NaOH.
Calculate the pH of this solution.
Question 28.
(6 marks)
A student carried out a titration experiment by adding hydrochloric acid
to 10.0 mL of 0.20 mol L-1 NaOH solution in a beaker. A pH probe was
placed in the beaker and measurements were taken at regular intervals as
acid was added from a burette. The student’s set up is shown below.
burette
4.0
pH meter
Beaker
containing
NaOH
magnetic stirrer
Volume HCl 0.0
added (mL)
pH
2.0
4.0
6.0
8.0
8.2
8.4
8.6
8.8 9.0 10.0 12.0
13.3 13.1 12.9 12.6 11.9 11.8 11.6 11.1 2.9 2.4 1.5
1.4
(a) Plot these values on the graph (shown on your answer sheet) and draw a smooth curve to
show the progress of the titration.
(b) Label the position of the end point on your graph.
(c) Calculate the concentration of the acid used. Show all working.
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