chemistry

1. which formula represents the empirical formula of a compound?
a c2h,o b c2h4o2 cc cehi2 d h202

2 the relative first ionisation energies of four elements with consecutive atomic numbers below 20
are shown on the graph.
one of the elements reacts with hydrogen to form a covalent compound with formula hx.
which element could be x?
b
a

first

ionisation

energy

/kj mol

d
cc
atomic number

3 in which structure are three atoms bonded together in a straight line?
a poly(ethene), +ch,ch,+-
b_ propane, c3hs
c _ silicon tetrachloride, sicl,
d sulfur hexafluoride, sfg¢

4 in the sodium chloride lattice the number of chloride ions that surround each sodium ion is called
the co-ordination number of the sodium ions.
what are the co-ordination numbers of the sodium ions and the chloride ions in the
sodium chloride lattice?
sodium ions chloride ions
a 4 6
b 6 4
cc 6 6
d 8 6
o—eoeoeoeoeoeoeocoeoeor~w~w—eoeo~eoeoxe_e—eeeeeaeeeeaeeeeeeeeaeeeoeaeeeeeoeoeoeoeoeeeeeeeeeeeeeeoeaeeeeeeeee

5 a fluorescent light tube has an internal volume of 400 cm” and an internal pressure of 200 kpa.
it is filled with 0.03 moles of an ideal gas.
what is the temperature of the gas inside the fluorescent light tube?
a 3.21x10'k
b 3.21 10°k
c 3.21x10°k
d 3.21 10°k

6 one of the reactions in a lead/acid cell is shown.
pb(s) + pbo.(s) + 4h*(aq) + 2s0,?(aq) > 2pbso,(s) + 2h,o(i)
which statement about this reaction is correct?
a lead is both oxidised and reduced.
b_ lead is neither oxidised nor reduced.
c_ lead is oxidised only.
d_ lead is reduced only.

7 lodine and propanone react according to the following equation.
i,(aq) + ch3coch3(aq) — ch3cochp2i(aq) + hi(aq)
if the concentration of propanone is increased, keeping the total reaction volume constant, the
rate of the reaction also increases.
what could be the reason for this?
a agreater proportion of collisions is successful at the higher concentration.
b_ the particles are further apart at the higher concentration.
c_ the particles have more energy at the higher concentration.
d_ there are more collisions between reactant particles per second at the higher concentration.

8 sulfur can be oxidised in two ways.
s(s) + o2(g) > so2(g) ah® = -296.5kj mol
2s(s) + 302(g) > 2so03(g) ah® = -791.4kj mol
sulfur trioxide can be made from sulfur dioxide and oxygen.
2s0,(g) + o29) > 2503(g)
what is the standard enthalpy change for this reaction?
a -1384.4kj mol
b -989.8kj mol
c -494.9kjmol*
d -198.4kj mor"

9 hydrogen iodide dissociates into hydrogen and iodine.
2hi(g) = hag) + l(g)
in an experiment, bmol of hydrogen iodide were put into a sealed vessel at pressure p. at
equilibrium, xmol of the hydrogen iodide had dissociated.
which expression for k, is correct?
xn x? b x? 2 c x? 2 d x?
(b-x)? (b-xy 4b(b— x) 4(b- xy

10 the diagram shows the distribution of molecular energies in a sample of gas at a temperature 7;.
the activation energy for an uncatalysed reaction of this gas, eaiuncat, is shown.
t,
proportion es (uncat)
of molecules
with a given :
energy
0 t
0 molecular energy e
which diagram correctly shows the new distribution and new activation energy, eaica), when the
temperature is increased to tz, and a catalyst is used that increases the rate of the reaction?
a b
lj ie; e cat)
. wy ' wy 1
proportion e fg ss. exiuncat) proportion ts i “\ ! e ues)
of molecules | / ss le of molecules / “a
f ‘ / si | fa(cat) f é / s|
with a given i se with a given fi i
energy ij i. o> energy ij ntt
r t j 8 t '
0 molecular energy e 0 molecular energy e
cc d
le excat) qt,
proportion . — ne atuncat) proportion 7 <5 eacuncat
‘a 1 st a se
of molecules git i sd of molecules iv sd —
with a given 4 ee with a given r4 ss
energy pts ~~ energy ler ~~
7 1 1 af 1 h
‘7 1 1 ‘4 1 1
0 0
0 molecular energy e 0 molecular energy e

11 200g of water are at 25°c.
the water is heated to 75°c by burning 2g of ethanol.
what is the amount of energy transferred to the water?
a 0.418kj b 10.4kj c 41.8kjd d 62.7kj

12 the elements cl, mg, si and s are all in period 3.
what is the correct sequence of the melting points of these elements, from lowest to highest?
lowest highest
melting point melting point

a cl ss mg si
b cl ss si mg
cc mg si ss cl
d si mg ss cl

13 an element y reacts according to the following sequence.
burns an excess of
in o, hcl(aq) naoh(aq) naoh(aq)
y ——— white solid ————~ solution ————~ white precipitate ———————~ solution
what could be element y?
a al b ca c mg dp

14 which compound would most usually be added to soil to reduce its acidity?
a aluminium hydroxide
b_ calcium hydroxide
c magnesium hydroxide
d sodium hydroxide

15 the mineral dolomite is a mixture of magnesium carbonate and calcium carbonate.
an aqueous reagent, x, was added to a small sample of dolomite. effervescence was seen and a
white solid, y, was formed.
what could be the correct identity of reagent x and solid y?
p| reasentx [sate |
a hydrochloric acid calcium chloride
b hydrochloric acid magnesium chloride
cc sulfuric acid calcium sulfate
d sulfuric acid magnesium sulfate

16 which fertiliser contains the greatest percentage of nitrogen by mass?
a ammonium nitrate, nhzno3
b ammonium sulfate, (nh4)2so,4
c_ diammonium hydrogen phosphate, (nh4)2hpo,
d urea, co(nh2)2

17 71.0g of chlorine, cl2, react with an excess of sodium hydroxide solution at a particular
temperature. the reaction produces exactly 35.5g of product x.
what is product x?
a h20 b_ nacl c naclo d nacilo;

18 compound q is a white crystalline solid which dissolves easily in water. vwwhen concentrated
sulfuric acid is added to a dry sample of q steamy white fumes are formed which, when passed
through aqueous silver nitrate solution, form a white precipitate. this precipitate is soluble in
dilute ammonia solution.

what could be the identity of compound q?
a agcl b nabr c nacl d  pbbr2

19 the strengths of the covalent bonds within halogen molecules, and the van der waals’ forces
between halogen molecules, vary going down group 17 from chlorine to bromine to iodine.
which row shows these correctly?
strength of strength of
covalent bonds van der waals’ forces
a decreases decreases
b decreases increases
cc increases decreases
d increases increases

20 the structural formula of compound q is shown.
[e)
ocr
q
how many stereoisomers exist with this structural formula?
a 1 b 2 cc 4 d 8

21 what is the name of compound x?
wwe
compound x
a _ trans-2-hydroxyhex-3-ene
b _ trans-2-hydroxyhexene
c _trans-5-hydroxyhex-3-ene
d __trans-5-hydroxyhexene

22 many, but not all, organic reactions need to be heated before a reaction occurs.
which reaction occurs quickly at room temperature, 20°c?
a cohy + bro > cohabro
b coh, + hx0 > ch3ch,0h
c chsch20h > c2hy + h20
d ch3;ch,0h + hbr — ch3ch2br + h,o0

23 asection of an addition polymer chain is shown.
—ch—ch,—ch,—ch—
by bi
which monomer could be used to make this polymer?
a  ch2chch2c1
b  ch2chci
c ch3chchci
d chcichch,ch2cl

24 which organic reaction is an example of nucleophilic substitution?
a ch3ch2br + naoh + ch2ch2 + h20 + nabr
b  ch3;ch2br + naoh — ch3ch2oh + nabr
c ch,ch2 + hcl > czhs5cl
d czhe + cl, > c2hscl + hcl

25 citric acid can be converted into tricarballylic acid in two stages. an intermediate, q, is formed.
ch,—co,h ch,—co,h
a ae sesh... q ae. de
tes ee bei eae
citric acid tricarballylic acid
which reagents are needed for each stage?
[seve [see |
a concentrated h2so,4 h2(g) and ni
b concentrated h.so, lialh,
cc lialh, h2so,(aq)
d naoh(aq) h2(g) and ni

26 glucose can be used to prepare sorbitol, a compound used as a sugar substitute.
h oh oh oh oh
oh oh
o — > ho
oh oh oh oh
glucose sorbitol
which reagent may be used for this conversion?
a acidified potassium dichromate(vi)
b_ sodium borohydride
c sodium hydroxide
d_ tollens’ reagent

27 3-methylbutanone is treated with alkaline aqueous iodine. the mixture of products is then
acidified.
which compound is present in the final mixture of products?
a 3-methylbutanoic acid
b__butanoic acid
c_ methylpropanoic acid
d_propanoic acid

28 at room temperature, propanoic acid was reacted to produce sodium propanoate. no gas was
produced during the reaction.
what could the propanoic acid have reacted with?
a nahco;(aq) b  naoh(aq) c na,co;(aq) d nazso,(aq)

29 ethene is reacted with steam in the presence of concentrated h3po,. the product of this reaction
is added to acidified potassium dichromate(vi) and heated under reflux for one hour. the final
organic product is collected and labelled x.

but-2-ene is treated with hot, concentrated, acidified potassium manganate(vii). the final
organic product is collected and labelled y.

which statement is correct?

a one molecule of x has more carbon atoms than one molecule of y.

b one molecule of y has more carbon atoms than one molecule of x.

c xand y have different functional groups.

d xis the same compound as y.

30 asample of the ester ch3ch2ch2co2ch2chs is hydrolysed. the product mixture is then treated
with hot, acidified kmno,.
what are the final carbon-containing products?
a ch3ch2co>h only
b  ch3co2h + ch3ch2co2h
c ch3;co2h + ch3ch2,ch2co2h
d ch3ch2oh + ch3ch2zch2,co2h

31 the definitions of many chemical terms can be illustrated by chemical equations.
which terms can be illustrated by an equation that includes the formation of a positive ion?
1 first ionisation energy
2 heterolytic fission of a covalent bond
3. enthalpy change of atomisation

32 a student makes sodium chloride by reacting together 0.025mol of sodium carbonate with an
excess of 0.2moldm™ hydrochloric acid.
nazco3 + 2hci > 2nacl + h,0 + co,
which statements about the quantities of substance are correct?
1 600cm? of carbon dioxide are produced at room temperature and pressure.
2 250cm* of the hydrochloric acid are needed to exactly neutralise the sodium carbonate.
3. 1.46g of sodium chloride are produced.

33 one way of recovering tin from old printed circuit boards is to dissolve it in a mixture of
concentrated hydrochloric acid and concentrated nitric acid. the tin dissolves because it reacts
with the mixture of these concentrated acids.

sn + 4hc1 + 2hno3 — sncly + no2 + no + 3h20
which statements about this reaction are correct?
1 nitrogen is present in three different oxidation states in the reactants and products.
2 the oxidation state of tin increases from 0 to +4.
3. the oxidation state of chlorine remains the same.

34 the following reaction takes place in a suitable solvent.
na*nh, + nh,*ci- > na*cl- + 2nh3
which statements explain why this reaction should be classified as a bronsted-lowry acid-base
reaction?
1. the ammonium ion acts as a proton donor.
2 na*ci isa salt.
3 ammonia is a nucleophile.

35 which statements about the elements barium and calcium and their compounds are correct?
1 barium nitrate decomposes at a higher temperature than calcium nitrate.
2 barium hydroxide is more soluble in water than is calcium hydroxide.
3. calcium is more reactive with water than is barium.

36 which statements explain why nitrogen gas is unreactive?
1 nitrogen atoms are highly electronegative.
2 nitrogen molecules are non-polar.
3. the triple bond between nitrogen atoms is very strong.

37 in which molecules do all the carbon atoms lie in the same plane?
1 = 2,3-dimethylbut-2-ene
2 propane
3 cyclohexane

38 a reaction pathway diagram is shown.
progress of reaction
which reactions would have this reaction pathway diagram?
1. (chs)3cbr + naoh -— (ch3)3;coh + nabr
2 chsch2ch2br + naoh — ch3ch2ch20oh + nabr
3 (ch3)3cch2ch2cl + 2nh3 — (ch3)3cch2ch2nh2 + nh,cl

39 the compounds below are used to make perfumes.
which compounds will produce a yellow precipitate with alkaline aqueous iodine?
1 2 3
oh
ho no - an
oh
oh

40 the reaction of ethanal, ch;cho, with hcn to form 2-hydroxypropanenitrile is catalysed by
nacn.
what are features of the intermediate of this reaction?
1 itis chiral.
2 it has asingle negative charge on one of its atoms.
3 it is a nucleophile.

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