Area of Study One – Practise Exam
To be completed in 75 minutes with 10 minutes reading time.
A Scientific Calculator is allowed to be used. No graphical calculators!
Marks Breakdown
Multiple Choice
Short Answer
Maximum 20 Marks
Maximum 41 Marks
Total Marks Available = 61
Section A
Multiple Choice Questions - Circle the most correct answer.
Question 1
Analysis of the components of a mixture using gas-liquid chromatography normally involves
measuring the
A. Rf values of components, using a gas as the mobile phase.
B. Rf values of components, using a liquid as the mobile phase.
C. retention time of components, using a gas as the mobile phase.
D. retention time of components, using a liquid as the mobile phase.
Question 2
Which one of the following analyses is best performed using atomic absorption
spectroscopy?
A. measuring the amount of potassium in salt
B. determining the amount of caffeine in coffee
C. measuring the carbonate content of mineral water
D. detecting the presence of ethanoic acid in a sample of wine
Question 3
Different quantities of nitrogen oxide (NO) are listed below.
Which one contains the least number of molecules?
A. 6 × 102 L at 273 K and 1 atm
B. 6 × 1023 molecules
C. 6 × 102 g
D. 6 mol
1
Question 4
When 2.54 g of solid iodine reacts with excess chlorine and the unreacted chlorine is
evaporated, 4.67 g of a yellow product remains.
The empirical formula of the product is
A. ICl2
B. ICl3
C. ICl4
D. ICl5
Question 5
Chromatogram 1 was obtained by analysis of a sample of a mixture of two sugars, A and B,
using high performance liquid chromatography (HPLC). Chromatogram 2 was obtained by
analysing another sample of the same mixture by HPLC under different conditions.
Consider the following changes which could be made to the operating conditions for HPLC.
I
decreasing the pressure of the mobile phase
II
decreasing the temperature
III
using a less tightly packed column
Which of the changes would be most likely to produce chromatogram 2?
A. I only
B. II only
C. III only
D. I and II only
Question 6
Which one of the following is least likely to be a product of a redox reaction between
sulfuric acid and zinc metal?
A. H2
B. H2S
C. SO2
D. SO3
2
Question 7
Which of the following statements would apply to compounds that belong to the same
homologous series?
I
they have similar physical properties
II
they have similar chemical properties
III
they contain the same functional group
IV
they have the same molecular formula but different structures
A. III only
B. IV only
C. II and III only
D. I, II, III and IV
Questions 8 and 9 refer to the following information.
One litre of an aqueous solution of potassium hydroxide (KOH) has a pH of 12.0 at 25°C.
Question 8
The amount of solid KOH, in mol, that must be added to the solution to raise the pH to 13.0
would be
A. 10.13
B. 10.12
C. 0.09
D. 0.10
Question 9
The amount of pure HCl gas, in mol, that must be added to the solution to lower the pH
from pH 12.0 to 2.0
would be
A. 10
B. 2.0
C. 0.02
D. 0.01
3
Question 10
Two bottles, I and II, have the same volume and are at the same temperature.
Bottle I contains 10 g of argon gas only.
Bottle II contains 10 g of neon gas only.
Compared to bottle I, the number of atoms and pressure in bottle II would be
number of atoms
pressure
A.
equal
the same
B.
equal
higher
C.
approximately double the same
D.
approximately double higher
Question 11
A sodium lamp emits yellow-coloured light. If the light from the lamp was passed through a
container of sodium vapour, it is likely that the light emerging from the container would
appear
A. brighter, due to electrons in atoms in the sodium vapour moving from higher to lower
energy levels.
B. brighter, due to electrons in atoms in the sodium vapour moving from lower to higher
energy levels.
C. duller, due to electrons in atoms in the sodium vapour moving from higher to lower
energy levels.
D. duller, due to electrons in atoms in the sodium vapour moving from lower to higher
energy levels.
Question 12
The flame test method of analysis can be used to distinguish between
A. methanol and ethanol.
B. sulfuric acid and nitric acid.
C. lithium nitrate and calcium nitrate.
D. sodium carbonate and sodium chloride.
Question 13
The molar volume of oxygen, in L, at 1.00 atmosphere and 100°C, is closest to
A. 30.6
B. 24.5
C. 22.4
D. 8.2
4
Question 14
Sulfuric acid (H2SO4) and nitric acid (HNO3) are both strong acids. Ethanoic acid (CH3COOH)
is a weak acid. 20.00mL solutions of 0.10M concentration of each of these three acids were
separately titrated with a 0.10M solution of sodium hydroxide (NaOH).
In order to react completely:
A. all three acids would require the same amount of NaOH.
B. HNO3 would require more NaOH than CH3COOH but less than H2SO4.
C. H2SO4 and HNO3 would require the same amount of NaOH but CH3COOH would require
less.
D. CH3COOH and HNO3 would require the same amount of NaOH but H2SO4 would require
more.
Question 15
A student used paper chromatography to separate two components, I and II, in a solution.
A spot of the solution was initially placed at the origin.
When the spot corresponding to component I (Rf = 0.50) had advanced 4.0 cm, the spot
corresponding to component II was 1.0 cm behind.
The Rf value of component II is closest to
A. 0.68
B. 0.38
C. 0.25
D. 0.13
Question 16
Consider the molecule CH3CH2CH2CH2CHClCH2CH3.
The systematic name of this molecule is:
A. 5-chloroheptane.
B. 3-chloroheptane.
C. 5-chlorooctane.
D. 3-chlorooctane.
Question 17
The number of structural isomers that are carboxylic acids with the formula C4H8O2 is
A. 1
B. 2
C. 3
D. 4
5
Question 18
The concentration of K+ ions in 100 mL of 0.0500 M K2CO3 solution, in g L-1, is
A. 0.196
B. 0.391
C. 1.96
D. 3.91
Question 19
Carbon monoxide can be oxidised to carbon dioxide.
2CO(g) + O2(g) → 2CO2(g)
3 mol of CO and 2 mol of O2 are mixed. When the reaction is complete there will be
A. 4 mol of CO2 produced.
B. 2 mol of CO2 produced.
C. 1 mol of CO unreacted.
D. 0.5 mol of O2 unreacted.
Question 20
The equation for a reaction that occurs during the extraction of iron from iron ore is
Fe2O3(s) + 3CO(g) → 2Fe(l) + 3CO2(g)
During this reaction the oxidation number of iron changes from
A. +3 to 0, and CO is the reductant.
B. +6 to 0, and CO is the reductant.
C. +3 to 0, and CO is the oxidant.
D. +6 to 0, and CO is the oxidant.
End Of Section A
6
Section B: Short Answer – Answer all questions in the spaces provided.
Question 1
The mass spectrum of 1-bromopropane is given below.
a) This spectrum shows the presence of two molecular ions.
i)
State the m/z at which these ions occur.
_______________________________________________________________________________________
1 mark
ii)
Account for the presence of two molecular ions.
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1 mark
b) i) State the formula of the fragment responsible for the peak at m/z 43.
_______________________________________________________________________________________
1 mark
iii)
Identify a fragment that could be responsible for the peak at m/z 44.
_______________________________________________________________________________________
1 mark
Total 4 marks
7
Question 2
Sulfur dioxide (SO2) is a chemical of major industrial significance.
a. SO2 gas can be produced in a reaction between concentrated sulfuric acid and nickel metal. A solution
containing Ni2+ ions is also formed.
Write balanced equations for the:
i. oxidation reaction
_____________________________________________________________________________________
ii. reduction reaction
_____________________________________________________________________________________
iii. overall reaction, showing the states of all reactants and products.
_____________________________________________________________________________________
1 + 1 + 2 = 4 marks
b. SO2 can also be produced in a chemical reaction between zinc sulfite (ZnSO3) and hydrochloric acid
according to the equation:
ZnSO3(s) + 2H+(aq) → Zn2+(aq) + SO2(g) + H2O(l)
Is this reaction also a redox reaction? Explain your answer.
_______________________________________________________________________________________
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1 mark
Total 5 marks
8
Question 3
A burette packed with finely divided alumina powder (Al2O3) was used to separate the components in a
plant extract by chromatography. The alumina acts as the stationary phase and water was used as the
mobile phase.
A solution of the plant extract was placed at the top of the alumina and, once it had been adsorbed,
further water was added periodically. The components separated as three coloured bands, as shown in the
diagram below.
a. i. In which one of the three bands, A, B or C, were the components most strongly adsorbed to the
stationary phase?
_______________________________________________________________________________________
ii. Band B starts to show signs of separating into two different bands just before it emerges from the
bottom of the burette. Give one possible modification that could be made to this experiment to more
effectively separate band B into its separate components.
_______________________________________________________________________________________
_______________________________________________________________________________________
1 + 1 = 2 marks
b. In another experiment, the components in the plant extract were separated in a similar way to paper
chromatography, using a glass sheet coated with alumina and water as the mobile phase. Which one of the
three bands, A, B or C, contains the component that would be most likely to have the smallest Rf value?
Explain your answer.
_______________________________________________________________________________________
_______________________________________________________________________________________
1 mark
9
c. Which one of the three bands, A, B or C, contains the component that would have the smallest retention
time if this separation was conducted using a high-performance liquid chromatograph with alumina (Al2O3)
as the stationary phase? Explain your answer.
_______________________________________________________________________________________
_______________________________________________________________________________________
1 mark
Total 4 marks
Question 4
A soluble fertiliser contains phosphorus in the form of phosphate ions (PO43-). To determine the PO43content by gravimetric analysis, 5.97 g of the fertiliser powder was completely dissolved in water to make a
volume of 250.0 mL.
A 20.00 mL volume of this solution was pipetted into a conical flask and the PO43- ions in the solution were
precipitated as MgNH4PO4.
The precipitate was filtered, washed with water and then converted by heating into Mg 2P2O7.
The mass of Mg2P2O7 was 0.0352 g.
a. Calculate the amount, in mole, of Mg2P2O7.
_______________________________________________________________________________________
_______________________________________________________________________________________
1 mark
b. Calculate the amount, in mole, of phosphorus in the 20.00 mL volume of solution.
_______________________________________________________________________________________
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1 mark
10
c. Calculate the amount, in mole, of phosphorus in 5.97 g of fertiliser.
_______________________________________________________________________________________
_______________________________________________________________________________________
1 mark
d. Calculate the percentage of phosphate ions (PO43-) by mass in the fertiliser. Ensure you express your
answer to an appropriate number of significant figures.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
3 marks
e. i. Several actions which could occur during this analytical procedure are listed below (A-D). For each
action, indicate the likely effect on the calculated percentage of phosphate ions in the fertiliser by placing a
tick in the appropriate box.
Action
Calculated result
would be too low
No effect on
calculated result
Calculated result
would be too high
The MgNH4PO4 precipitate was not washed
with water
The conical flask had been previously
washed with water but not dried
A 25.00mL pipette was unknowingly used
instead of a 20.00mL pipette
The mass of the fertiliser was recorded
incorrectly. The recorded mass was 0.2g
higher than the actual mass
ii. In the case of action B above, explain your reasoning for the answer that you have given.
_______________________________________________________________________________________
_______________________________________________________________________________________
4 + 1 = 5 marks
Total 11 marks
11
Question 5
A green dye used to colour tinned peas is made by mixing the yellow chemical, curcumin, with another
colouring agent called bright blue. The individual spectra of curcumin, bright blue and a typical green dye
are represented below.
UV-visible spectroscopy is used to analyse the curcumin content of tinned peas.
a. Circle the wavelength below which would be best used for absorbance measurements to determine the
curcumin content of the peas.
400 nm
450 nm
500 nm
550 nm
600 nm
650 nm
1 mark
b. In one analysis, a stock solution of curcumin was prepared by dissolving 0.100 g of curcumin (C21H20O6;
molar mass = 368.0 g mol-1) in 250.0 mL of water.
The stock solution was then diluted to make the following three standard solutions.
12
The absorbances of the standard solutions at the chosen wavelength were measured and the following
calibration line was obtained.
i. Calculate the concentration of curcumin in the stock solution in mol L-1.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
ii. What volume of water must be added to 10.0 mL of the stock solution to make standard 3?
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
iii. The curcumin in a 9.780 g sample of peas was extracted into solution. The solution was filtered and
made up to 100 mL in a volumetric flask. The absorbance of the solution at the wavelength used in the
above calibration was found to be 0.170.
Calculate the curcumin content of the peas in milligram per gram of peas.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
2 + 2 + 3 = 7 marks
Total 8 marks
13
Question 6
Sulfur dioxide gas is commonly used as a preservative in wine. An important source of SO 2 is solid sodium
metabisulfite (Na2S2O5; molar mass 190 g mol-1). Na2S2O5 reacts readily with acid as follows.
Na2S2O5(s) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + 2SO2(g)
a. Calculate the volume, in litres, of SO2 produced at 1.00 atm pressure and 15.0oC when 250 g of Na2S2O5
reacts with excess acid.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
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3 marks
b. The concentration of an aqueous solution of SO2 (solution A) is to be determined using its reaction with
an aqueous solution of tri-iodide ions (I3-). The relevant half reactions are:
SO2(aq) + 2H2O(l) → 4H+(aq) + SO42-(aq) + 2eI3-(aq) + 2e- → 3I-(aq)
50.0 mL of a 0.0125 M solution of I3- is added to 50.0 mL of solution A, providing excess of I3-. The final
100.0 mL solution is called solution B.
i. Write an overall balanced chemical equation for the reaction that occurs, identifying the substance that
is the reductant.
Equation _____________________________________________________________________________
Reductant_________________________
14
ii. Calculate the amount, in mol, of I3- added to solution A.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
iii. The excess I3- remaining in the solution is determined by titration with a standard solution of sodium
thiosulfate (Na2S2O3). The equation for the reaction is
S2O32-(aq) + I3-(aq) + H2O(l) → 3I-(aq) + S2O42-(aq) + 2H+(aq)
14.70 mL of a 0.00850 M solution of Na2S2O3 reacts exactly with all the I3- remaining in solution B.
Calculate the original concentration of SO2 in solution A.
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
_______________________________________________________________________________________
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2 + 1 + 3 = 6 marks
Total 9 marks
15