chemistry

1. which feature is present in both ethene and poly(ethene)?
a bond angles of 109°
b~ xcovalent bonds
c_ ocovalent bonds
d sp’ orbitals
a

2 the electronic configuration of an atom of sulfur is 1s*2s*2p°3s“3p".
how many valence shell and unpaired electrons are present in one sulfur atom?
valence shell unpaired
electrons electrons
a 2 1
b 4 2
cc 6 0
d 6 2

3 in which pair does the second substance have a lower boiling point than the first substance?
a coh, and c2h;cl
b  ch3;0ch3 and c2hs0h
c neand ar
d  ch3nh2 and czh,¢

4 compound j burns in excess oxygen to give carbon dioxide and water only. when a 3.00g
sample of compound j is burnt in excess oxygen, 4.40g of carbon dioxide and 1.80g of water are
formed.

what is the empirical formula of j?
a ch b cho c ch, d ch.,0

5 the gases x and y react to form z.
x(g) + y(g) = z(g)
an equilibrium mixture of these three gases is compressed at constant temperature.
what will be the changes in the mole fraction of z and in k,?
a increase increase
b increase no change
cc no change increase
d no change no change

6 which gas is likely to deviate most from ideal gas behaviour?
a hcl b he c ch d no
i i eee

8 sulfur reacts with concentrated nitric acid in a redox reaction.
s + 4hno3 > so2 + 4no2 + 2h,0
what are the changes in oxidation number of sulfur and of nitrogen in this reaction?
[[sator[ nitoaen |
a +2 -3
b +2 -1
cc +4 -3
d +4 -1

9 materials can be classified by their chemical structures. four common types of structure are
metallic, ionic, simple molecular and giant molecular.
some physical properties of four substances are shown in the table.
which substance has a simple molecular structure?
melting point effect of electrical
[°c adding water conductivity

a 64 reacts good when solid

b 113 insoluble always poor

cc 767 soluble good when solid

d 1600 insoluble always poor

10 ina particular reversible reaction the yield of product is increased

e if the temperature is increased;

e if the pressure is decreased.
which equation could describe this reversible reaction?
a ch,(g) + h20(g) = 3h2(g) + co(g) ah = +206kj mol"
b 4nh3(g) + 30.(g) = 2n2(g) + 6h,o(g) ah =-227kjmol'
c 2no.(g) = n20,(g) ah =-58kj mol
d 30,(g) = 203(9) ah = +143kj mol

11 a chemical company used a catalyst in a chemical process. the company has now decided not
to use the catalyst but to increase the temperature so that the rate of the reaction is the same as
it was when the catalyst was used.

which statement about the new conditions compared to the original conditions is correct?
a_ the activation energy has been decreased.

b_ the activation energy has been increased.

c_ there are fewer successful collisions per unit time.

d_ there are more successful collisions per unit time.

12. which oxide does not react with cold, dilute sodium hydroxide to produce a salt?
a al,03 b p.o cc so, d_ ssio,

13 the graphs show trends in four physical properties of elements in period 3, excluding argon.
which graph has electronegativity on the y-axis?
a b
na mg al si p s cl na mg al si p s cl
cc d
na mg al si p s cl na mg al si p s cl

14 in this question, x represents an atom of chlorine, bromine or iodine.
which explanation for the variation in volatility down group 17 is correct?
a instantaneous dipole-induced dipole forces between molecules become stronger.
b permanent dipole-permanent dipole forces between molecules become stronger.
c_ the bond energy of the xz molecules decreases.
d_ the first ionisation energy x(g) > x*(g) +e decreases.

15 to manufacture cement, 1000 million tonnes of limestone are decomposed each year. to
manufacture lime for agriculture, 200 million tonnes of limestone are decomposed each year.
what is the total mass of carbon dioxide in million tonnes produced from these two processes in
a year?

a 440 b 528 cc 660 d 880

16 in group 2 of the periodic table, the properties of the elements and their compounds show
regular change down the group.
which property shows a decrease from magnesium to barium?
a_ the decomposition temperature of the carbonates
b_ the decomposition temperature of the nitrates
c the solubility of the hydroxides
d_ the solubility of the sulfates

17 when concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced,
along with a number of other products. however when concentrated sulfuric acid is added to solid
sodium chloride only hydrogen chloride and sodium hydrogensulfate are produced.

what is the reason for this difference?

a_ bromine is less volatile than chlorine.

b_ hydrochloric acid is a weak acid.

c_ sulfuric acid is not an oxidising agent.

d_ the bromide ion is a stronger reducing agent than the chloride ion.

18 ihe dative covalent bond can be represented by an arrow, —>. ihe arrow points towards the
atom receiving the lone pair.
which diagram of an ammonium ion is correct?
a b cc d
h * h - h + h -
it to a it
| | | |

19 sulfur dioxide can be catalytically oxidised by an oxide of nitrogen in the atmosphere.
which reaction shows the regeneration of the catalyst?
a no + 202 = 2no2
b 4nh3 + 502 > 4no + 6h20
c ne + o2 > 2no
d no + 40, + no;

20 compound y is treated with an excess of hydrogen gas in the presence of a nickel catalyst. the
product is fully saturated.
~% is
compound y
what is the number of chiral carbon atoms in the product?
a 5 b 6 cc 7 d 8

21 which equation represents a valid propagation step in the chlorination of ethane?
a cohe + cle — czhscl + he
b  cohscl + cle — czhscle + hcl
c cyhscl + he - cohse + hcl
d chse + cle — czhscl

22 maleic acid is used in the food industry and for stabilising drugs. it is the cis-isomer of butenedioic
acid and has the structural formula ho>c?ch=chco>h.
what is the product formed from the reaction of maleic acid with cold, dilute, acidified
manganate(vii) ions?
a  hozcch(oh)ch(oh)co2h
b  ho,cco2h
c hozcch2ch(oh)co2h
d ho,ccococo,;h

23 primary halogenoalkanes undergo hydrolysis reactions.
which reaction would occur most rapidly if they are all warmed to the same temperature?
a c2hsbr with h2o
b  c,hsbr with naoh(aq)
c czhscl with ho
d  czhscl with naoh(aq)

24 structural isomerism and stereoisomerism should be considered when answering this question.
a colourless liquid, cs5h1,cl, exists as a mixture of two optical isomers.
when heated with sodium hydroxide in ethanol, a mixture of only two alkenes is formed.
what could the colourless liquid be?
a (ch3ch2)2chc1
b  ch3ch2zch2chcich;
c (ch3),>chchcich3
d ch3ch2ccl(ch3)2

25 when warm water is added to halogenoalkane x, an sy1 reaction occurs.
agno(aq) is then added; a yellow precipitate is formed.
what could be x?
a 1-chlorobutane
b_ 1-iodobutane
c  2-chloro-2-methylpropane
d  2-iodo-2-methylpropane

26 which alcohol will react with an acidified solution of potassium dichromate(vi) to produce a
ketone containing six carbon atoms?
a 2,2-dimethylbutan-1-ol
b  2-methylpentan-3-ol
c  3,3-dimethylpentan-2-ol
d  3-methylpentan-3-ol

27 which statement about butanone is correct?
a_ butanone can be dehydrated by concentrated sulfuric acid to give ch2=chch=ch)p.
b_ butanone gives a positive result with tollens’ reagent.
c_ butanone reacts with hcn by an electrophilic addition mechanism.
d_ butanone reacts with nabh, to give a chiral product.

28 ethanal, ch3cho, is used to make product r in a three-stage synthesis.
hcn h,so,(aq), conc. h,so,

/nacn reflux (a few drops)
ch,cho ——————» product p ———————» productq ———————~» product r
two molecules of q react to give one molecule of r plus two molecules of water.
r has two ester functional groups in each molecule. r does not react with sodium.
what is the empirical formula of r?
a cho b  c3h4o2 c c3hso2 d = céhi005

29 ihe ester ethyl dutanoate can be hyarolysed using an excess of dilute sodium hydroxide solution.
which substance is a product of this reaction?
a ch3ch2ch2co2na
b  ch;co2na
c ch3;ch20na
d h20

30 the infra-red spectrum of an organic compound is shown.
100
transmittance
% 50
0
4000 3000 2000 1500 1000 500
wavenumber/cm™'
which compound could give this spectrum?
a  ch3ch2co3h
b  ch3ch(oh)ch;
c chscoch;
d ch3;coch20oh

31 for complete combustion, 1 mol of an organic compound x requires 2.5 mol of oo.
which compounds could be x?
1. cshs0h
2 coh
3 ch3;cho

32 in which pairs do both species have the same number of electrons?
1 *cland *’cl
2 *cr and “ar
3 “ar and “°k*

33 for which reactions does the value of ah® represent both a standard enthalpy change of
combustion and a standard enthalpy change of formation?
1 c(s) + o2(g) > coz(g)
2 2c(s) + o2(g) > 2co(g)
3 co(g) + 402(g) > coz(g)

34 the temperature of a reversible gas phase reaction is increased.
which statements are always correct?
1 more product is present at equilibrium.
2 +the average speed of the particles increases.
3 there are more successful collisions per unit time.

35 three samples of chlorine gas each contain 0.710g of chlorine. each sample is reacted with a
reagent.
e inthe first reaction a sample is reacted completely with hydrogen gas.
e inthe second reaction a sample is reacted completely with cold naoh(aq).
e inthe third reaction a sample is reacted completely with hot naqh(aq).
which masses of the named products would be formed?
1 exactly 0.730g of hc1 form in the first reaction.
2 exactly 0.585 g of nacl form in the second reaction.
3. exactly 0.975 g of nacl form in the third reaction.

36 solid barium oxide is added to some ammonium sulfate solution in a test-tube and the mixture is
warmed. a piece of damp red litmus paper is held over the mouth of the test-tube.
which observations would be made?
1. the damp litmus paper initially turns from red to blue.
2  awhite precipitate forms in the test-tube.
3 a brown gas is evolved with strong heating.

37 which compounds show geometrical (cis-trans) isomerism?
1. ch3ch=c(ch3)c2hs
2 chsch=chch2ch2ch3
3) c2hsch=chc2hs

38 which pairs of compounds may be distinguished from each other by testing with alkaline aqueous
iodine?
1. ethane-1,2-diol and ethanol
2. propan-2-ol and methylpropan-2-ol
3. ethanol and butan-2-ol

39 the diagram shows an experimental set-up which can be used in several different experiments.
silica, alumina
—_ or baked clay
liquid x on
mineral wool gas collected
support ss
senn ss
sees
ee. >
=
| strong gia
heat =0-
gentle a ep ey elougm or
heat paras eal te ee is ye pet
era rial a0 =f scwater
which processes could be demonstrated by using the above apparatus?
1 oxidation of ethanol (liquid x)
2 dehydration of ethanol (liquid x)
3. cracking of paraffin (liquid x)

40 the ester c2,h;co2ch2ch2ch3 can be made in a school or college laboratory by a sequence of
four reactions or fewer using compound z as the only organic material.
what might be the identity of compound z?
1. ch3ch2,ch2oh
2 ch3ch,cho
3 chscoch;

Solve 9701_s18_qp_12