chemistry

1 compound x consists of 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass.
what is the empirical formula of compound x?
a ch,0 b  c.h20 c c2h,o d cho

2 which statement is correct?
a 1.0g of hydrogen gas contains 3.0 x 107° atoms.
b_  4.0g of helium gas contains 1.2 x 10 atoms.
c 16g of methane gas contains 3.0 x 104 atoms.
d 44g of carbon dioxide gas contains 6.0 x 107° atoms.

3. technetium (tc) is a second row transition element that does not occur naturally on earth. one of
its isotopes has 56 neutrons.
what is the nucleon number of this isotope?
a 43 b 56 cc 99 d 112

4 which atom has more unpaired electrons than paired electrons in orbitals of principal quantum
number 2?
a carbon
b nitrogen
c oxygen
d fluorine

5 atom x is the central atom in a molecule.
in this molecule, atom x has four pairs of valence electrons in its outer shell.
the four pairs of valence electrons include at least one bond pair and at least one lone pair.
what could be a possible shape for the molecule?
a linear
b_ non-linear
c trigonal bipyramidal
d trigonal planar

6 which molecule has the largest overall dipole?
a b cc d
cl cl h cl
a f /
c=c oo=c oo=c oo=c=o
f \ \ ‘
cl cl h cl

8 the general gas equation can be used to calculate the value of the m, of a gas.
for a sample of a gas of mass m grams, which expression will give the value of m,?
a mat og pe pet og pe oy on ge by
pv m rt mrt

9 the equation for the formation of ammonium chloride is shown.
nh3(g) + hcl(g) == nh,cl(s) ah =-314kjmol™
which diagram shows the correctly labelled reaction pathway diagram for the decomposition of
ammonium chloride?
a b
e, \ nh, + hci nh, + hci
energy energy e,
ah ah
nh,cl nh,c1
progress of reaction progress of reaction
cc d
nh,cl / fa nh,cl
energy energy ex
ah ah
nh, + hcl nh, + hcl
progress of reaction progress of reaction

10 in a catalytic converter in the exhaust system of a car, carbon monoxide is oxidised to carbon

dioxide, and nitrogen monoxide is reduced to nitrogen.
what are the changes in oxidation number of carbon and nitrogen in these two processes?
[| eerten | ritoaen

a -2 +2

b -1 +1

cc #1 -1

d +2 -2

11. no and no; are both present in the lower atmosphere as pollutants.
the reaction sequence shows the production of ozone from oxygen in the lower atmosphere.
this sequence repeats many times.

no2(g) >» no(g) + o(g)
no(g) + 402(g) > no2(g)
o2(g) + o(g) > os(g)
which statement about this reaction sequence is correct?
a nois acting as a catalyst, but noz is not acting as a catalyst.
b- nobis acting as a catalyst, but no is not acting as a catalyst.
c_ neither no nor no, are acting as catalysts.
d_ both no and no; are acting as catalysts.

12 a mixture of two period 3 oxides are added to water. a solution forms with a ph of just below 7.
what could be the constituents of the mixture?
a al,03 and mgo
b  na,o and mgo
c nazo and p4019
d s03 and p4010

13 which statement about the compounds of the group 2 metals is correct?
a barium carbonate is less thermally stable than strontium carbonate.
b_ barium sulfate is less soluble than magnesium sulfate.
c_ calcium hydroxide is less soluble than magnesium hydroxide.
d_ calcium nitrate is more thermally stable than strontium nitrate.

14 a0.005mol sample of anhydrous calcium carbonate is completely thermally decomposed to give
100 cm? of gas.
in a separate experiment carried out under the same conditions, a 0.005mol sample of
anhydrous calcium nitrate is completely thermally decomposed. the volume of gaseous products
is measured.
what total volume of gaseous products is produced from the calcium nitrate?
a 50cm? b 100cm° c 200cm* d 250cm*

15 redox reactions are common in the chemistry of group 17 elements.
which statement is correct?
a br ions will reduce cl2 but not iz.
b cl2 will oxidise br~ ions but not i” ions.
c_ fy, is the weakest oxidising agent out of f2, cl2, bry and ip.
d_ ti ions are the weakest reducing agent out of f°, cl’, br andt.

16 silver chloride and silver iodide form equilibria when added to water.
agcl(s) = ag*(aq) + cl(aq) k,= k,
agl(s) = ag*(aq) + t(aq) k. = kp
each equilibrium position lies well to the left.
silver iodide will not dissolve in aqueous ammonia. silver chloride will dissolve in aqueous
ammonia. another equilibrium is formed.
ag*(aq) + 2nh3(aq) == ag(nhs)o"(aq) ke = kg
the position of this equilibrium lies to the right.
what is the order of magnitude for these three equilibrium constants?
[sales —= ages |
a ks kk k;
b kg k, ka
cc kp kk, kg
d ky kk kg

17 xis the ion of a metal which burns with a red flame.
y is an ion that reacts with concentrated h2so, to produce h2s.
what could be the formula of a compound containing x and y?
a babro b bal, c srbro d sri.

18 oxides of nitrogen are present in the environment due to natural and man-made sources.
which row is correct?
[ [ature source ofivogen ones | man-made source ofnivegen ones |
a electrical discharges in the atmosphere internal combustion engines
b electrical discharges in the atmosphere as a by-product of the haber process
cc decomposition of dead plants in rivers internal combustion engines
d decomposition of dead plants in rivers as a by-product of the haber process

19 magnesium hydroxide dissolves in aqueous ammonium chloride, but not in aqueous sodium
chloride.
which statement explains this observation?
a. the ionic radius of the nh,’ ion is similar to that of mg?* but not that of na’*.
b  nh,cldissociates less fully than nacl
c_ the na* and mg”* ions have the same number of electrons.
d_ the nh,’ ion can donate a proton.

20 the formula of hydrocortisone acetate is shown.
hydrocortisone acetate
0. ch,ococh,
ho hs | on
ch,
(6)
which row is correct?
number of c atoms number of chiral atoms
in one molecule in one molecule

a 22 7

b 22 8

cc 23 4

d 23 8

21 bromomethane, chsbr, decomposes in the stratosphere forming methyl free radicals and
bromine free radicals.
which row correctly describes this decomposition?
ivoeot bond fiesion number of electrons in
yp a bromine free radical
a homolytic 35
b heterolytic 35
cc homolytic 36
d heterolytic 36

22 structural and stereoisomerism should be taken into account when answering this question.
y is a gaseous hydrocarbon which decolourises aqueous bromine. it contains no rings.
10.0g of y occupies a volume of 3.43 dm® under room conditions.

how many isomeric structures are possible for y?
a 4 b 5 cc 6 d 7

23 which equation represents a valid propagation step in the chlorination of ethane?
a cohscl + cle — czhycle + hcl
b c2he + cle — czhscl + he
c cyhscl + he — cohg* + hcl
d cohs* + cle > cohscl

24 butanoic acid can be made from 1-bromopropane in two stages.
stage 1 ch3ch2,ch2br - ch3ch2ch2cn
stage 2. chs3ch2ch2cn — ch3ch2ch2co2h
which types of reaction are stage 1 and stage 2?
[| sage [tage 2
a electrophilic addition hydrolysis
b electrophilic addition oxidation
cc nucleophilic substitution hydrolysis
d nucleophilic substitution oxidation

25 a halogenoalkane has the molecular formula csh;;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_1-bromo-2,2-dimethylpropane

26 compound p is heated under reflux with an excess of acidified potassium dichromate(vi) to form
compound q.
compound q has a lower boiling point than compound p.
what could be compound p?
a 2-methylbutan-1-ol
b  2-methylbutan-2-ol
c_pentan-1-ol
d_pentan-2-ol

27 structural and stereoisomerism should be taken into account when answering this question.
an organic compound, x, is dehydrated by heating with concentrated phosphoric(v) acid.
only two organic products are formed.

what could be x?
a b cc d
oh oh
oh “~ oh

28 which compound produces a precipitate with 2,4-dinitrophenylhydrazine reagent and also with
alkaline aqueous iodine?
a _ butan-2-ol
b butanal
c_ butanone
d_pentan-3-one

29 organic compound z has an alcohol group and a carboxylic acid group.
compound z reacts with magnesium carbonate to make a salt with a relative formula mass of
230.3.
compound z does not react with acidified potassium manganate(vii).
what could be the identity of compound z?
a 2-hydroxy-2-methylbutanoic acid
b= 2-hydroxy-2-methylpropanoic acid
c  3-hydroxy-2-methylbutanoic acid
d  3-hydroxy-2-methylpropanoic acid

30 the infra-red spectrum of y is shown.
100
transmittance /%
50
0
4000 3000 2000 1500 1000 500
wavenumber/cm
what could y be?
a ch3co2c2hs
b  ch2(oh)ch=chch,0h
c chs3(ch2)2,co2h
d  ch2(oh)(ch2)2,cho

31 the boltzmann distribution diagram shows a fixed amount of a gas at two different temperatures,
t, and to.
t,
t, activation
energy

number of

particles with 1

energy, e j

0 t
0) molecular energy, e

which statements correctly describe the features of this diagram?
1 temperature t;, is lower than temperature 72.
2 the shaded area indicates the particles that have sufficient energy to react at to.
3. the total area under each curve is the same for both temperatures.

32 four solutions, each of concentration 0.1 moldm™, were tested with a ph meter. the results are
shown.
[aan [emotes fo

acid 1 ch3co2h 4

acid 2 hno3 1

base 1 ch3nh2 11

base 2 naoh 14
which statements explain these results?
1 acid 2 has a lower ph than acid 1 because it is more soluble.
2 base 2 has a higher concentration of hydroxide ions in solution than base 1.
3 acid 1 dissociates less than acid 2.

33 which reactions are redox reactions?
1 mg + 2hci + mgcl2 + ho
2  2k2cro, + 2h* — k2cr207 + 2k* + h20
3  cuco; + 2hcl + cucl, + h,0 + co,

34 when the liquid naf, is heated, it decomposes into a single product, x.
which statements are correct?
1 n-f bonds are broken during this decomposition.
2 the enthalpy change when n2f, decomposes into x is approximately +160 kj mol”.
3 molecules of x are non-linear.

35 the following statements compare some properties of the oxides and chlorides of sodium and
silicon.
which statements are correct?
1. the melting point of sic1, is higher than the melting point of sioz.
2 ~~ sicl, reacts with water, nacl does not.
3 the melting point of sic, is lower than the melting point of nacl.

36 which statements about ammonium chloride are correct?
1 it reacts with hot aqueous sodium hydroxide to produce an alkaline gas.
2 insolution, it reacts with aqueous silver nitrate to produce a white precipitate.
3 when solid, it reacts with concentrated sulfuric acid to produce chlorine.

37 what is the same for a pair of optical isomers?
1 their empirical formula
2 their functional groups
3 their structural formula

38 which of the molecular formulae represent at least one compound that can undergo addition
polymerisation?
1. cyhs
2 c2h3cl
3 c3h.o

39 which of the reactions give products containing a chiral centre?
1. ch2(oh)coco>h + an excess of hcn
2 ch,(oh)coco;h + an excess of nabh,
3 ch(oh)coco2h + an excess of liialh,

40 ethyl butanoate is heated with a dilute aqueous solution of sodium hydroxide.
which substances are products of this reaction?
1. sodium butanoate
2 ~water
3. sodium ethanoate

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