chemistry

1. which statement about enthalpy changes is correct?
a_ enthalpy changes of atomisation are always negative.
b_ enthalpy changes of combustion are always positive.
c_ enthalpy changes of formation are always positive.
d_ enthalpy changes of neutralisation are always negative.

2 beams of charged particles are deflected by an electrical field. the angle of deflection of a
particle is proportional to its charge/mass ratio.
in an experiment protons are deflected by an angle of +15°. in another experiment under identical
conditions 7h” ions are deflected by an angle of y°.
what is the value of y?
a -30.0 b -7.5 c +75 d +30.0

3 rubidium and bromine form ions that are isoelectronic. each ion has 36 electrons.
which row is correct?
rubidium radii a

/bromide radii
a atomic < ionic atomic < ionic
b atomic < ionic atomic > ionic
cc atomic > ionic atomic < ionic
d atomic > ionic atomic > ionic

a ee

4  inwhich set do all the molecules have all their atoms arranged in one plane?
a aicl3, bf3, phs
b_ aicl3, coz, nh3
c_ bfs3, c2h4, c3he
d chs, co2, ho

5 flask x contains 5dm? of helium at 12kpa pressure and flask y contains 10 dm? of neon at 6kpa
pressure.
if the flasks are connected at constant temperature, what is the final pressure?
a 8kpa b 9kpa c 10kpa d 11kpa

6 exactly 1.00g of a metallic element reacts completely with 300. cm* of oxygen at 298k and 1atm
pressure to form an oxide which contains o* ions.
the volume of one mole of gas at this temperature and pressure is 24.0dm’.
what could be the identity of the metal?
a calcium
b magnesium
c_ potassium
d_ sodium

8 ammonium metavanadate, nh,vo3, can be used to make a solution containing vo2c/, which
contains chloride ions.
what is the change in the oxidation number of vanadium in this reaction?
a -1 b o cc +1 d +2

9 in this question, all pressures are measured in atm.
the equation represents the equilibrium between three gaseous substances x, y and z.
x + 3y = 22
at temperature t,, the numerical value of k,, the equilibrium constant, is 2.
at a higher temperature to, the partial pressures at equilibrium are as shown.
which row is correct?
[eae | a
value of k, at tz reaction is

a 54/25 endothermic

b 54/25 exothermic

cc 25/54 endothermic

d 25/54 exothermic

10 in a chemical system the particles involved have a range of energies. this can be shown on a
graph called the boltzmann distribution.
which statement correctly explains the effect of a catalyst on the particles in a chemical system?
a_ a catalyst enables particles with a lower energy to collide successfully.
b_ acatalyst increases the number of particles with higher energies.
c_ acatalyst increases the number of particles with the most probable energy value.
d_ a catalyst increases the value of the most probable particle energy.

11 nitrogen and hydrogen can react together to form ammonia.
the formation of ammonia is exothermic.
the rate and yield of the reaction can be altered by changing the conditions under which the
reaction is carried out.
which row shows the effects of adding iron to the mixture and increasing the temperature?
[attire ———*dcneveasing the temperate |
a has no effect on the equilibrium yield reduces the equilibrium yield
b increases the equilibrium yield increases the equilibrium yield
cc increases the equilibrium yield increases the rate
d increases the rate has no effect on the equilibrium yield

12 the melting points of the period 3 elements phosphorus to argon are shown in the table.
toonen ps | | |
which factor explains the changes in melting points from phosphorus to argon?
a_ the changes in electronegativity from phosphorus to argon
b_ the changes in first ionisation energy from phosphorus to argon
c the increase in the number of electrons in each atom from phosphorus to argon
d the number of atoms in each molecule of the element from phosphorus to argon

13 which observations are made when a sample of silicon chloride, sicl,, is added to a beaker of
water?
a_ no visible change is observed.
b steamy fumes and a precipitate are both observed.
c_ the appearance of a precipitate is the only observation.
d_ the appearance of steamy fumes is the only observation.

14 a 4.00g sample of an anhydrous group 2 metal nitrate is heated strongly until there is no further
change. a solid residue of mass 1.37 g is formed.
which metal is present?
a barium
b calcium
c magnesium
d - strontium

15 in which row are all statements comparing magnesium and barium correct?
| ese ase a
a higher lower faster slower
b higher lower slower faster
cc lower higher faster slower
d lower higher slower faster

16 which statement about the halogens is correct?

a __lodine cannot behave as an oxidising agent.

b_ the volatility of the elements increases from chlorine to iodine because of the increase in
molecular size down the group.

c when an equimolar mixture of chlorine and hydrogen is exploded, only one product is
formed.

d when concentrated sulfuric acid is added to solid sodium bromide, hydrogen sulfide is one of
the products.

17 chlorine reacts with both hot and cold sodium hydroxide to form products containing chlorine.
cold sodium hydroxide forms sodium chlorate(x) and hot sodium hydroxide forms sodium
chlorate(y). x and y are oxidation numbers.

which equation is correct?
a y=x-6 b y=x-4 c y=x+4 d y=x+6

18 the product of the contact process is z.
which reaction or process leads to the formation of a gas that can neutralise an aqueous solution
of z?
a_ atmospheric lightning
b combustion of fuel in an internal combustion engine
c_ the haber process
d_ thermal decomposition of group 2 nitrates

19 if ammonium cyanate is heated in the absence of air, the only product of the reaction is urea,
co(nhz2)2. no other products are formed in the reaction.
what is the formula of the cyanate ion present in ammonium cyanate?
a con. b con,” c ocn™ d ocn*

20 [here are three structural isomers with the formula cshyp2.
which formulae correctly represent these three structural isomers?
a ch3ch2ch2ch2ch3 ch3ch(ch3)ch2ch3 c(chs)4
b ch3;ch2ch2,ch,ch3; ch3ch(ch3)ch2zch3; ch3;ch2ch(ch3)ch3
(¢: ss et ae sg -_<
° al, ws, ah, an

21 the diagram shows a molecule that has o bonds and x bonds.
i
ch,==ch— ch, —c—-o— ch, — ch=ch,
how many o bonds are present in this molecule?
a 15 b 17 cc 18 d 21

22 polyethene is made by the polymerisation of ethene.
which statement is correct?
a the monomer and the polymer have different empirical formulae.
b the monomer can be oxidised without heat whereas the polymer cannot.
c the monomer can be used as a fuel whereas the polymer cannot.
d the monomer has greater van der waals’ forces than the polymer.

23 compound p reacts separately with koh(aq) and hbr.
ch2zchch2ch,c1
compound p
what are the mechanisms of these two reactions?
[ere
a nucleophilic addition electrophilic addition
b nucleophilic addition free radical substitution
cc nucleophilic substitution electrophilic addition
d nucleophilic substitution free radical substitution

24 which statement about compound q is correct?
ch,c==chch,ch,
lacie,
q
h ch,
a it could be polymerised to give a polymer with the repeat unit tt ‘
loscr, vcs
ci cl
b it reacts with chlorine by a free radical mechanism to give cucu___¢-—du—cu, :
boot, |
oh oh
cit reacts with cold, dilute acidified manganate(vii) to give cn¢——¢-—cryeu, .
loscr, |
br br
d_ it reacts with bromine via a free radical mechanism to give ch, —¢—_—b-—cr,cu, :
loc, |

25 a halogenoalkane has the molecular formula cs5h;;br. the halogenoalkane does not form an
alkene when treated with ethanolic sodium hydroxide.
what could be the halogenoalkane?
a 1-bromo-2-methylbutane
b  2-bromo-2-methylbutane
c  3-bromopentane
d_bromodimethylpropane

26 the reactions of four organic compounds are given in the table.
which compound could be propan-2-ol?
reagent/ observations
when oxidised with cr.077-/h*, gives when added to ethanoic acid, and a
an organic product with a boiling point few drops of conc. h2sox, gives a
greater than the original compound sweet-smelling compound

a no no

b no yes

cc yes no

d yes yes

27 compound x has the empirical formula c2h30.
compound x reacts with 2,4-dinitrophenylhydrazine reagent to give an orange precipitate and
also decolourises warmed acidified potassium manganate(vii) solution.
what could be the identity of x?
a b
vite it |
\ yj
ae h—c—c—c—c—h
/ | | a | | |
h h h h h o 4h
cc d
ho o fe) h h h h o
n\.7f
h “cw 4 \ i lt tol g
| | /s c—c—c— c-—-c—c
h—c—c=c / | | | jn
| \ ho  h h h h h
h h

23 compound y gives methanol and sodium etnanoate on treatment with aqueous sodium
hydroxide.
what is the structure of y?
a  ch3co2ch3
b  hco,c3hs
c ho,cch,cho
d hoch2zch,cooh

29 which compound can be used to make propanoic acid by treatment with a single reagent?
a = ch2=chch2ch3
b  ch3ch2ch2cn
c ch3ch(oh)cn
d ch3ch(oh)ch3

30 the infra-red spectrum of compound l is shown.
100
transmittance
%
50
0
4000 3000 2000 1500 1000 500
wavenumber /cm-'
what could be the structure of l?
a hoch2coch20oh
b hoch,ch(oh)cho
c hoch2ch(oh)ch20h
d hoch2ch2cooh

31 zinc reacts with hydrochloric acid according to the following equation.
zn + 2hcl > zncl2 + ho

which statements are correct?

1 a3.27g sample of zinc reacts with an excess of hydrochloric acid to give 0.0500 mol of zinc
chloride.

2 a6.54g sample of zinc reacts completely with exactly 100cm? of 1.00 mol dm hydrochloric
acid.

3 a 13.08g sample of zinc reacts with an excess of hydrochloric acid to give 9.60dm® of
hydrogen, measured at room conditions.

32 the melting point of chlorine is lower than the melting point of iodine.
which statements help to explain this difference?
1 _lodine has more electrons than chlorine and so has stronger van der waals’ forces.
2. aniodine molecule is more polar than a chlorine molecule.
3 the covalent bonds between iodine atoms are stronger than the covalent bonds between
chlorine atoms.

33 aqueous iron(ii) sulfate can take part in redox reactions.
6feso, + 7h2so4 + nazcr207 > 3fe2(so,)3 + cro(so4)3 + na2zso4 + 7h20
which redox changes occur during this reaction?
1 fe(ii) is oxidised to fe(iii).
2  cr(vi) is reduced to cr(iii).
3 oxygen is reduced to water.

34 the equation represents an equilibrium.
4nh,(g) + 502(g) == 4no(g) + 6h2o(g) ah = -900 kd mol"
what would increase the concentration of no at equilibrium?
1 areduction in the reaction temperature
2 the use of a suitable catalyst
3. anincrease in the total pressure

35 asample containing xmol of alcl, is dissolved in water to give solution w.
in order to precipitate all of the aluminium as its hydroxide, ymol of sodium hydroxide are
required.
more of the alkali is added to re-dissolve the precipitate, giving solution z.
which statements are correct?
1 the initial ph of solution w is below 7
2 y=3x
3  zcontains xmol of aluminium

36 which statements concerning calcium hydroxide are correct?
1 it is less soluble in water than strontium hydroxide.
2 when it is added to water an alkaline solution is formed.
3 it is used in agriculture to lower soil ph.

37 which bromopropenes would react with cold bromine in the dark to form a product containing a
chiral carbon atom?
1. chbr=chch3;
2 ch ,=chch,br
3. ch =cbrch;

38 halogenoalkanes can undergo reaction with hydroxide ions.
rbr + oh” — roh + br-
the reaction of some halogenoalkanes proceeds by the sy1 mechanism.
which statements about the sy1 mechanism are correct?
1. acarbocation is formed which is stabilised by the inductive effect of the alkyl groups present.
2 only tertiary halogenoalkanes are hydrolysed in this way.
3. the intermediate formed includes a carbon atom with five bonds attached to it.

39 which statements about 2-methylbutan-1-ol are correct?
1 it can give hc1(g) on reaction with pcls.
2 itcan be oxidised to give an aldehyde.
3 it displays optical isomerism.

40 the compound cis-hex-3-enal is responsible for the characteristic smell of cut grass.
%
cis-hex-3-enal
which reagents will react with cis-hex-3-enal?
1 sodium
2 sodium borohydride
3. fehling’s reagent

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