chemistry

1. which contains the largest number of hydrogen atoms?
a 0.10 mol of pentane
b 0.20 mol of but-2-ene
c 1.00 mol of hydrogen molecules
d 6.02 x 10” hydrogen atoms

2 in which pair of species do both species have only one unpaired p electron?
a ar andc b bandti* c fandga d se and si-

3 phosphorus forms two chlorides. phosphorus(ii) chloride, pcls, is a covalent liquid.

phosphorus(v) chloride is an ionic solid. one of the ions present is [pcy].
what is the shape of the pc/3; molecule and the [pc1,]* ion?
ee

a pyramidal square planar

b pyramidal tetrahedral

cc tetrahedral square planar

d trigonal planar tetrahedral

4 ah is the standard enthalpy of formation of methane.
ah$ is the standard enthalpy of combustion of carbon.
ah3 is the standard enthalpy of combustion of hydrogen.
ah®
ch4(g) + 202g) ———> co,(g) + 2h20(!)
which expression is equivalent to ah? ?
a ah$ — ah$ + ah§
b ah = 2ah8 = ah§
c ah§ — ah3 + ah?
d ah§ + 2ah8 — ah§

¥3 [ne diagram snows the boltzmann aistridbution tor the same gas at two alirerent temperatures, /,
and to.
t,
t,
y
0
0 x
what is plotted on the y-axis and which line represents the higher temperature?
| | plotted on y-axis higher temperature
a number of molecules ty
b number of molecules to
cc molecular energy ty
d molecular energy to

6 what is the minimum mass of oxygen required to ensure the complete combustion of 12dm* of
propane measured under room conditions?
a 60g b 80g c 120g d 160g

7 why is the first ionisation energy of oxygen less than that of nitrogen?
a_ the nitrogen atom has its outer electron in a different subshell.
b_ the nuclear charge on the oxygen atom is greater than that on the nitrogen atom.
c_ the oxygen atom has a pair of electrons in one p orbital that repel one another.
d_ there is more shielding in an oxygen atom.

8 which gas would behave most like an ideal gas under room conditions?
a helium
b_ nitrogen
c ammonia
d_ krypton

9 when hydrogen iodide is reacted with concentrated sulfuric acid, several reactions occur,
including:
8hi + h2so,4, > h2s + 4h20 + 41,
which row gives the change in oxidation number of iodine and of sulfur in this reaction?
change in oxidation change in oxidation
number of iodine number of sulfur
a -1 +6
b -1 +8
cc +1 -6
d +1 -8

10 the diagram represents the haber process for the manufacture of ammonia from nitrogen and
hydrogen.
heat exchanger
n, + h, ——>
catalytic
converter
condenser
nh,
what is the purpose of the heat exchanger?
a_tocool the incoming gas mixture to avoid overheating the catalyst
b_tocool the reaction products and separate the nh; from unused nz and h2
c_ to warm the incoming gas mixture and shift the equilibrium to give more nh3
d_ to warm the incoming gas mixture and speed up the reaction

11. which statement about catalysts is correct?
a_ they change the reaction pathway by increasing the activation energy.
b_ they increase the rate of reaction by lowering the enthalpy change of the reaction.
c_ they increase the number of particles that have sufficient energy to react.
d heterogeneous catalysts are in the same state as the reactant.

12 element x is in period 3. element x forms a solid oxide y.
y reacts with hot concentrated hydrochloric acid. y reacts with hot aqueous sodium hydroxide to
form a compound in which x is part of an anion.
how many p electrons does one atom of x have in its outer shell?
a 0 b 1 cc 2 d 3

13 the gaseous products of heating a mixture of ca(oh). and nh,cl are passed through solid cao.
a single gaseous product, w, is collected.
a sample of w reacts with cl2(g) to produce two gases, x and y.
xis an element. y is acidic.
y reacts with w to produce z.
what are x and z?
p| x | zz |
a no cacly
b no nh,cl
cc oz cacl,
d o2 nh,cl

14 q is a mixture of a group 2 oxide and a group 2 sulfate. q contains equal amounts of the two
compounds.
q is shaken with water and the resulting mixture filtered; a solid residue is obtained. there is no
reaction when the solid residue is shaken with hcl(aq). shaking the filtrate with h2so,(aq)
produces a white precipitate.
what could be q?
a bao + baso,
b bao + mgso,
c mgo + baso,
d mgo + mgso,

19 which substance will not be a product of the thermal decomposition of hydrated
magnesium nitrate?
a dinitrogen monoxide
b magnesium oxide
c oxygen
d_ steam

16 a 5cm* sample of 0.05moldm™ sodium chloride is mixed with a 5cm* sample of 0.05moldm™?
potassium iodide. 10cm® of acidified 0.05moldm”™ silver nitrate is then added, followed by
concentrated ammonia solution.

what is seen after the addition of an excess of concentrated ammonia solution?
a acream precipitate

b  awhite precipitate

ca yellow precipitate

d_ no precipitate

17 the volatility of the group 17 elements, chlorine, bromine and iodine, decreases down the group.
what is responsible for this trend?
a bond length in the halogen molecule
b__ bond strength in the halogen molecule
c_ electronegativity of the halogen atom
d number of electrons in the halogen atom

18 acid rain is a dilute solution of sulfuric acid.
which pollutant also contributes to the formation of acid rain?
a carbon monoxide
b_ carbon dioxide
c nitrogen dioxide
d_ hydrocarbons

19 ris an oxide of period 3 element t. 5.00g of r contains 2.50 g of t.
what is t?
a magnesium
bs aluminium
c silicon
d © sulfur

20 bromoethane reacts with cyanide ions, producing propanenitrile.

which statement about the sy2 mechanism of this reaction is correct?

a the lone pair of electrons on c of cn’ attacks the carbon atom of the c—br bond.

b_ the lone pair of electrons on c of cn’ attacks the carbocation formed when the c—br bond
breaks.

c_ the lone pair of electrons on n of cn’ attacks the carbon atom of the c—br bond.

d_ the lone pair of electrons on n of cn’ attacks the carbocation formed when the c—br bond
breaks.

21 which compound would produce two different carboxylic acids when treated with hot,
concentrated, acidified manganate(vij) ions?
a b cc d

22 vvnicn compound could show botn cis-frans isomerism and optical isomerism?
a b cc d
cl oy cl oy oo br cl oy
\ \. \ \
a k 4 zh poe ial at a
c=c br —— = c=¢ cl ec if
/ \ , * / \ f *
br h i h cl h br h

23 limonene is a hydrocarbon found in the rind of citrus fruits.
limonene
what is the molecular formula of limonene?
a crohi2 b crohi4 cc crohi6 d crohis

24 the compound cetyl palmitate, c;5h3;co2c1¢h33, is a waxy solid.
cetyl palmitate is heated under reflux with an excess of aqueous sodium hydroxide.
which products will be formed?
a cish3i10na and cish33co2na
b  cish31co2na and cigh330na
c cish3,0h and cygh33;3co2na
d cysh3i1co2na and cigh330h

25 when an organic compound is oxidised, any oxygen atom gained by the organic molecule is
considered to be from a water molecule also producing 2h* + 2e™. any hydrogen atom lost may
be considered to be lost as h* + e.

these changes can be represented by the following two equations.
h2o -> [o] + 2h* + 2e°
[h] > h+ e&

compound x is oxidised by heating under reflux with hot, acidified potassium dichromate(vi) for
one hour. the half-equation for the reduction reaction is shown.

cr207* + 14h* + 6e > 2cr** + 7h20
under these conditions, one mole of potassium dichromate(vi) oxidises three moles of x.
what could x be?
a propanal
b_propan-1-ol
c _propan-1,2-diol
d_propan-1,3-diol

26 compound x has the empirical formula c2h,o. its infra-red spectrum is shown.
100
transmittance /%
50
0
4000 3000 2000 1500 1000 500
wavenumber/cm~
what could be the skeletal formula of compound x?
a b cc d
a oh oo
pe as o o,
a en
h oh

27 how many moles of hydrogen, h2, are evolved when an excess of sodium metal is added to
one mole of citric acid?
citric acid
co,h
a ee
laie
a 05 b 1.5 cc 2 d 4

28 which statement is correct for the reaction of carbonyl compounds with hcn?
a_ the reaction is catalysed by concentrated h2sox,.
b_ pentan-2-one and hcn react to give a chiral product.
c_ the reaction is a condensation reaction.
d_ the reaction is nucleophilic substitution.

29 the table describes four reactions of propene.
which row is correct?
name of main
reagent used 4

organic product
a aqueous bromine 2-bromopropane
b cold acidified aqueous potassium manganate(vii) propane-1,3-diol
[e hydrogen chloride 2-chloropropane
d steam propan-1-ol

30 butanoic acid is prepared from 1-bromopropane.
this synthesis requires a sequence of two reactions.
which compound is prepared in the first stage of the synthesis?
a 1-aminopropane
b_propan-1-ol
c butanal
d _butanenitrile

31 ethanol combines with ethanoic acid to form ethyl ethanoate according to the following reaction.
c2hsoh(l) + ch3co2h(i) == ch3co2c2hs(1) + h2o(i) ah® =-6kj mol
9.2g ethanol, 12g ethanoic acid and 8.8g ethyl ethanoate are mixed and allowed to stand at
298 k, until equilibrium is reached.
(m,: c2hs0h, 46; ch3co2h, 60; ch3co2c2hs, 88)
the resulting equilibrium mixture is found to contain 4.8 g ethanoic acid.
the experiment is repeated at 323 k.
which statements are correct?
1. there are 0.22 moles of ethyl ethanoate in the mixture at equilibrium at 298 k.
2 the equilibrium mixture at 323 k will contain more than 4.8 g of ethanoic acid.
3. if asmall amount of water is added at the start of either experiment the value of k, would not
be affected.

32 the diagram shows an incomplete energy profile diagram for a reaction.
products
enthalpy
reactants
progress of reaction

which reactions could this diagram refer to?
1 caco;(s) > cao(s) + co2(g)
2 hg) > 2h(g)
3 cl (aq) ~ cl(g) + aq

33 a gaseous hydrocarbon has a density of 2.42 gdm ~ under room conditions.
what could be the skeletal formula of this hydrocarbon?
1 fo
: a
3 asa

34 which molecules contain at least one bond angle of 120°?
1. coh,
2 pfs
3 ncls3

35 which statements are correct going across period 3 from sodium to chlorine?
1. the charge on the nucleus increases, pulling the electrons closer to it.
2 the radius of the most common ion of each element decreases.
3. the shielding caused by inner electrons decreases, so the outer electrons are pulled closer
to the nucleus.

36 which statements are correct?
1 magnesium carbonate decomposes at a lower temperature than calcium carbonate.
2 calcium hydroxide is more soluble in water than magnesium hydroxide.
3 calcium is a stronger reducing agent than magnesium.

37 which statements are correct?
1 1,1-difluoroethane is less reactive than 1,1-dichloroethane.
2 1,1-difluoroethane is polar.
3 the c-f bond is stronger than the c—cl bond.

38 which pairs of compounds may be distinguished by testing with alkaline aqueous iodine?
1. butanal and butanone
2 pentan-2-one and pentan-3-ol
3. propanone and propan-2-ol

39 which reactions have a coloured organic product?
1. ethanal + 2,4-dinitrophenylhydrazine reagent
2 ethanol + acidified potassium dichromate(vi)
3 ethene + cold dilute acidified potassium manganate(vi1)

40 propanoic acid is reacted with an excess of lithium aluminium hydride. the organic product of this
reaction is reacted with ethanoic acid in the presence of concentrated sulfuric acid, forming
product x.

what are major commercial uses of x?
1 fuel

2 solvent

3 flavouring

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