O LEVEL PAST PAER
QUESTIONS.______________________________________________________________________________TOPIC
2: Experimental Techniques
1- A gas Y, is less dense than air, very soluble in water and is
an alkali.Which method is used to collect a dry sample of the gas?
C[J03/Q2]2- What is the most suitable way of investigating the
different food colourings in some drinks?A- crystallisation B-
filtration C- fractional distillation D- paper
chromatography[DO3/Q1] 3- Potassium nitrate crystals can be
separated from sand using the four processes shown below. Which of
the following shows the processes in the correct order. First
lastABCDfilter
dissolvedissolvedissolvedissolveevaporateevaporatefilterevaporatecrystallinefilterevaporatecrystallinefiltercrystallinecrystalline
[D01/Q3]4-The equation for the reaction between aqueous lead(
II) nitrate and aqueous potassium iodide is shown.
Which method could be used to separate the products?A
chromatographyB crystallisationC distillationD filtration
[JO3/Q1]5- The diagram shows the chromatogram of four different
sugars using the same solvent.Glucose has an Rf value of 0.5.Which
sugar is glucose? C[DO4/Q2]
6- The diagram shows apparatus used to separate hexane (boiling
point, 70 oC) and heptane(boiling point, 98 oC).
Which graph would be obtained if the temperature at point T was
plotted against the total volumeof distillate collected? A
[DO4/Q4]7- Substance X melts at 53 oC and boils at 100 oC. It
does not dissolve in water and it does not reactwith water.Which
diagram shows the method most suitable for separating X from a
mixture of X and water? C
[NO5/Q2]8- Which test could be used to show that a sample of
water is pure?A It freezes at exactly 0 oC.B It turns anhydrous
copper(II) sulphate blue.C It turns cobalt(II) chloride paper
pink.D When it evaporates, it leaves no residue. [JO6/Q4]9- An
aqueous solution of compound X reacts with aqueous sodium hydroxide
to form a greenprecipitate and then aluminium powder is added. The
mixture is heated and a gas that turnsdamp red litmus paper blue is
given off.What is X?A ammonium nitrateB copper(II) chlorideC
iron(II) nitrateD iron(III) chloride [NOV -2006/Q3]
10- Which of the following reagents could be used to distinguish
between dilute nitric acid and dilutehydrochloric acid?A aqueous
barium chlorideB copper(II) carbonateC aqueous silver nitrateD
aqueous sodium hydroxide [NOV -2006/Q4] 11- The scheme shows some
reactions of a compound Y.What could the compound Y be?A aluminium
sulphateB calcium carbonateC copper(II) carbonateD zinc carbonate
[NOV -2006/Q5]
12- A mixture of two substances is spotted on to a piece of
chromatography paper.The paper is inserted into a beaker containing
a liquid.
For separation of the substances to occur the mixture mustA be
placed so that the spot is just below the level of the liquid.B be
soluble in the liquid.C contain substances of the same Rf values.D
contain substances that are coloured. [J07/Q2]13- Which pair of
substances are both mixtures?A air; waterB limewater; waterC
sea-water; airD sea-water; ethanol [J07/Q3]14-The diagram shows a
simple laboratory apparatus for the preparation and collection of a
dry gas.What is the gas?A carbon dioxideB chlorineC hydrogenD
hydrogen chloride [J07/Q4][J10/Q1]15- Which gas burns in air to
form a single product?A ammoniaB carbon monoxideC hydrogen chloride
D methane [J07/Q34]16- Oxygen was prepared from hydrogen peroxide
and collected as shown in the diagram. The first few tubes of gas
were rejected because the gas was contaminated by A water vapour. B
hydrogen peroxide. C hydrogen. D nitrogen.
[J08/Q1]17- The diagram shows the chromatogram obtained by
analysis of a single dye.Three measurements are shown. B
[J08/Q7]18- Which method could be used to obtain charcoal from a
mixture of powdered charcoal with sodiumchloride?A chromatographyB
filtration after shaking with waterC heating the mixtureD
distillation [N08/Q2]19- The diagram shows a chromatogram of
several inks.
Which statement is correct?A Black ink can be made by mixing
green, red and yellow inks.B Brown ink can be made by mixing blue
and red inks.C Yellow ink can be used to make brown ink.D Yellow
ink may be present in green ink. [J09/Q2]20- The oxidation of
ethanol to ethanoic acid is often carried out in the apparatus
shown. What is the purpose of the condenser? A to prevent air
reacting with the ethanoic acid B to prevent any ethanol from
escaping C to prevent the ethanoic acid changing back to ethanol D
to prevent the ethanoic acid reacting with the ethanol [J09/Q3]
21- The diagram shows a simple laboratory apparatus for the
preparation and collection of a dry gas. What is the gas? A carbon
dioxide B chlorine C hydrogen D hydrogen chloride
22- A mixture containing equal volumes of two liquids that mix
completely but do not react together isplaced in the apparatus
shown and heated until the thermometer first shows a steady
reading.At which position will there be the highest proportion of
the liquid with the higher boiling point? D
23- The two statements are about the fractional distillation of
crude oil. The statements may or maynot be correct. They may or may
not be linked.statement 1 Fractional distillation is used to
separate crude oil into useful fractions.statement 2 The fractions
with lower boiling points are found at the top of the
fractionatingcolumn.What is correct about these two statements?A
Both statements are correct and statement 2 explains statement 1.B
Both statements are correct but statement 2 does not explain
statement 1.C Statement 1 is correct but statement 2 is incorrect.D
Statement 1 is incorrect but statement 2 is correct. [J10/Q34]24-
The boiling points of various gases found in the air are shown
below. B
If the air is cooled, the first substance to condense is
water.If the temperature is lowered further, what is the next
substance to condense?A argonB carbon dioxideC nitrogenD oxygen
[N10/Q1]25- The fractional distillation apparatus shown is to be
used for separating a mixture of two colourlessliquids. A
thermometer is missing from the apparatus.Where should the bulb of
the thermometer be placed? B [N10/Q3]
26- Copper(II) sulfate crystals are separated from sand using
the four processes listed below.In which order are these processes
used? D[J11/Q2]
27- The labels fell off two bottles each containing a colourless
solution, one of which was sodiumcarbonate solution and the other
was sodium chloride solution.The addition of which solution to a
sample from each bottle would most readily enable the bottlesto be
correctly relabelled?A ammoniaB hydrochloric acidC lead(II)
nitrateD sodium hydroxide [N11/Q2]28- In a titration between an
acid (in the burette) and an alkali, you may need to re-use the
sametitration flask.Which is the best procedure for rinsing the
flask?A Rinse with distilled water and then with the alkali.B Rinse
with tap water and then with distilled water.C Rinse with tap water
and then with the acid.D Rinse with the alkali. [N11/Q3]29- When
dilute hydrochloric acid is added to a white powder a gas is
produced.The solution remaining is tested separately with small
volumes of both aqueous ammonia andaqueous sodium hydroxide.A white
precipitate is produced in both tests.What is the white powder?A
aluminium oxideB calcium oxideC copper(II) carbonateD zinc
carbonate [J12/Q3]30- A mixture of two substances is spotted onto a
piece of chromatography paper.The paper is inserted into a beaker
containing a liquid. [J12/Q4]
For separation of the substances to occur the spot of mixture
mustA be placed so that the spot is just below the level of the
liquid.B be soluble in the liquid.C contain substances of the same
Rf values.D contain substances that are coloured. [J12/Q4]31- Which
reagent could be used to distinguish between dilute nitric acid and
dilute hydrochloricacid?A aqueous barium chlorideB aqueous silver
nitrateC aqueous sodium hydroxideD copper(II) carbonate [J12/Q4]32-
When the rubber bulb of the dropper in the diagram is squeezed, the
aqueous silver nitrate dropsinto the aqueous sodium chloride and a
white precipitate of silver chloride is formed. What happens to the
total mass of the bottle and contents? A It increases due to the
formation of the heavy precipitate. B It remains the same because
only a physical change has taken place. C It decreases because heat
is evolved. D It remains the same because none of the products
escapes from the bottle. [J12/Q12]
33- Which ion reacts with aqueous ammonia to give a precipitate
that dissolves in an excess ofammonia?A Al3+(aq) B Fe2+(aq) C
Fe3+(aq) D Zn2+(aq) [J12/Q19]34- Which process would destroy the
bacteria in water?A chlorinationB desalinationC filtrationD
treatment with carbon [J12/Q34]35- Which is a property of hydrogen
gas?A It burns in air.B It has an unpleasant smell.C It relights a
glowing splint.D It turns moist litmus paper red. [N12/Q1]36-
Hydrogen chloride is very soluble in water, whereas chlorine is
only slightly soluble in water.Both gases can be dried using
concentrated sulfuric acid.Which diagram represents the correct
method of obtaining pure dry chlorine from damp chlorinecontaining
a small amount of hydrogen chloride? B [N12/Q3]
37- A
38- Which mixture could best be separated by using a separating
funnel?A oil and sandB oil and waterC sodium chloride and sandD
sodium chloride and water [June 2013/1]39- Which process involves
boiling a liquid and condensing the vapour?A crystallisationB
distillationC evaporationD filtration [June 2013/1]40- The diagram
shows the fractionation of crude oil.Which statement is correct?A
Each fraction consists of a single compound.B Fraction P has the
highest boiling point.C The highest temperature is at the top of
the column.D The naphtha fraction is used as feedstock for the
chemical industry. [Nov 2013/3]
41- The apparatus shown is used to distil a dilute solution of
ethanol in water.[B.P.: ethanol, 78 C; water 100 C]
Which graph shows the change in concentration of the ethanol in
the boiling flask as thedistillation proceeds? C
Paper -2 1- Sorrel is a small green plant.(a) The pigments in
the sorrel leaf can be separated by chromatography.
(i) Describe how chromatography can be used to separate
different pigments. [2]
(ii) Explain what is meant by Rf value. [1]
(b) Sorrel plants contain a poisonous carboxylic acid X.What can
be deduced about X from each of the following three pieces of
information?(i) When X is warmed with acidified potassium
manganate(VII), the solution changes frompink to colourless.
[1]
(ii) Aqueous bromine is not decolourised when added to a
solution of X. [1]
(iii) A 0.1 mol/dm3 solution of X has a pH of 3 whereas a 0.1
mol/dm3 solution of hydrochloric
acid has a pH of 1. [1](c) Analysis of 10.0 g of carboxylic acid
X shows that it contains 2.67 g carbon, 0.220 g hydrogen and 7.11 g
oxygen.
(i) Deduce the empirical formula of X. [3]
(ii) The relative molecular mass of X is 90. Deduce the
molecular formula of X. [1]
[Total: 10]2- Barium is a reactive metal in Group II of the
Periodic Table.Barium reacts with water in a similar way to sodium.
The products of the reaction are aqueousbarium hydroxide and a
colourless gas.(a) Barium sulfate is an insoluble compound.Describe
how a pure dry sample of barium sulfate is prepared from aqueous
bariumnitrate..........................................................................................................................................................
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...............................................................................................................................................................................................................................................................................................................[4]3-
Small pieces of a silver coloured metal, X, were added to
concentrated nitric acid. A browngas, Z, and a colourless solution
containing salt Y were formed.Analysis of a 0.0914 mol sample of Z
showed it contained 1.28 g of nitrogen and 2.93 g ofoxygen.The
small sample of the colourless solution was diluted with water and
then divided into twoportions. To one portion, aqueous sodium
hydroxide was added drop by drop until it was inexcess. A white
precipitate, W, was formed that redissolved in the excess
sodiumhydroxide. To the other portion, aqueous ammonia was added
drop by drop until it was inexcess. A white precipitate, W, was
formed that redissolved in the excess ammonia.(a) (i) Name the
white precipitate, W.
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[1](ii) Construct the ionic equation, with state symbols, for the
formation of W.
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[2](b) Name X and Y.X is
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Y is
..............................................................................................................................................[2](c)
(i) Calculate the relative formula mass, Mr, for gas Z. Mr =
................................................. [2](ii) Determine
the molecular formula for Z.
molecular formula..[2][Total : 9]Many fertilisers contain
phosphate ions and nitrate ions.(a) Explain why farmers put
fertilisers on the soil.
.....................................................................................................................................................[1](b)
Why should the chemicals in fertilisers be soluble in
water?.....................................................................................................................................................[1](c)
Ammonium nitrate, NH4NO3, and ammonium sulfate, (NH4)2SO4, are
commonly used infertilisers.(i) Calculate the percentage of
nitrogen by mass in ammonium nitrate.
[3](ii) Describe how crystals of ammonium sulfate can be
prepared from
aqueousammonia..........................................................................................................................................................
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..............................................................................................................................[4](d)
The formula of calcium phosphate is Ca3(PO4)2.Use this formula to
deduce the charge on the phosphate ion.
.....................................................................................................................................................[1][Total
: 10]