chemistry

1. ethene can be oxidised to form epoxyethane, c2h,o.
c2h4(g) + $o2(g) == c2h4o(g) ah® = -107 kj mol
which set of conditions gives the greatest yield of epoxyethane at equilibrium?
ieauite temperature
p 1°c
a high 100
b high 200
cc low 100
d low 200

2 cobalt can form the positive ion co(nhs3)4cl2°.
what is the oxidation number of cobalt in this ion?
a +1 b +2 cc +3 d +6

3 when considering one molecule of ethene, which row describes both the hybridisation of the
atomic orbitals in the carbon atoms and the overall bonding?
[| ryersaton [borne
a sp? 4.0 bonds 1 x bond
b sp” 5 o bonds 1 2 bond
cc sp° 4 0 bonds 1 x bond
d sp° 5 o bonds 1 2 bond

4 10cm? of ethane is burned in 45cm° of oxygen at a pressure of 101kpa and a temperature of
200°c. complete combustion takes place.
what is the total volume of gas present when the reaction is complete, measured under the same
conditions?
a 30cm? b 50cm® c 55cm* d 60cm*

5 two reactions are shown.
h2(g) > 2h(g)
co(g) + 302(9) > co2(g)

if molar amounts are used, how can the two energy changes associated with these reactions be
described?
a enthalpy of atomisation and enthalpy of combustion
b_ enthalpy of atomisation and enthalpy of formation
c_ bond energy and enthalpy of combustion
d_ bond energy and enthalpy of formation

6 [he diagram snows the boltzmann energy distribution curves tor molecules of a sample of a gas
at two different temperatures.
which letter on the axes represents the most probable energy for molecules of the same sample
of gas at the lower temperature?
a cacao
b / i)
c od

8 in this question you should use changes in oxidation numbers to balance a chemical equation.
acidified potassium dichromate(vi) solution can oxidise a solution of v7* ions. the equation for
this reaction is shown.

acr,0;7 + bv* + ch* > dcr* + evos + fh20
what is the ratio a:b in the correctly balanced equation?
a 1:1 b 1:2 c 2:1 d 4:1

10 in which pair does each species have the same number of unpaired electrons?
a aland cu*
b  caand cr*
c caand ni*
d fe* and 07

11. asample of solid ammonium chloride decomposes on heating.
solid ammonium chloride — ammonia gas + hydrogen chloride gas
a total of 2.4 x 107! molecules of gas is formed.
how many hydrogen atoms are present in the gaseous products?
a 1.2 107! b 2.4 x 107" c 4.8 x 107" d 9.6 x 107!

12 a white powder is a mixture of sodium chloride and sodium iodide. it is dissolved in water in a
test-tube. an excess of aqueous silver nitrate is added to the test-tube. a precipitate, x, is
observed.

an excess of concentrated ammonia is then added to the test-tube containing x. after the
test-tube has been shaken, a precipitate, y, is observed.

which statement about x or y is correct?

a xisa pure white colour.

b_ xis pure silver iodide.

cy is pure silver chloride.

d_ yis yellow.

13 6.90g of an ammonium sait is heated with an excess of aqueous sodium hyaroxide. ihe volume
of ammonia produced, measured under room conditions, is 2.51 dm’.
which ammonium salt is used?
a ammonium carbonate (m, = 96.0)
b ammonium chloride (m, = 53.5)
c ammonium nitrate (m, = 80.0)
d ammonium sulfate (m, = 132.1)

14 an excess of mgo is shaken with water. the resulting mixture is filtered into test-tube p.
an excess of bao is shaken with water. the resulting mixture is filtered into test-tube q.
which oxide reacts more readily with water and which filtrate has the lower ph?
[eras

readily with water filtrate of lower ph
a bao p
b bao q
cc mgo p
d mgo q

15 element z has a giant structure.
the chloride of z reacts with water to give a solution with a ph less than 5.
which pair shows two elements which could be z?
a aluminium, magnesium
b aluminium, silicon
c_ phosphorus, magnesium
d phosphorus, silicon

16 sodium, aluminium and silicon are three elements in period 3. each element forms an oxide.
which row has three correct properties of these oxides?
[| sedumoxde [amin oide | —_siiondionde
a basic basic amphoteric
b giant ionic giant ionic simple molecular
cc high melting point low melting point high melting point
d reacts with water no reaction with water no reaction with water

17 0.25g of anhydrous magnesium nitrate is heated strongly until it completely decomposes.
what is the total volume of gas produced, measured under room conditions?
a 40cm> b 81cm* c 101cm* d 202cm?

18 astatine, at, is below iodine in group 1/ of the perioaic | able.
which statement is most likely to be correct?
a agat(s) reacts with an excess of dilute aqueous ammonia to form a solution of a soluble
complex.
b_ astatine and kcl(aq) react to form kat(aq) and chlorine.
c_ kat(aq) and dilute sulfuric acid react to form hat(g).
d_ naat(s) and concentrated sulfuric acid react to form astatine.

19 what is the order of increasing melting point of the three chlorides shown?
ccl, mgcl2 pcls
lowest highest
melting point melting point

a ccl, pcls mgcl.
b mgclz ccl, pcls
cc mgcl, pcls; ccl,
d pcls ccly mgcl2

20 the skeletal formula of compound x is shown.
[e)
which row is correct?
mieleeuiar observation on
addition of x to
formula of x mie
fehling’s reagent
a c7h140 no change
b c7h140 red precipitate forms
cc c7h1g0 no change
d c7h1g0 red precipitate forms

21 which statement is correct?
a 2,2-dimethylpropanoic acid is an isomer of propyl methanoate.
b  2-methylbutan-2-ol is an isomer of hexan-3-ol.
c 3-methylbutan-2-one is an isomer of pentanal.
d  3,3-dimethylbutan-2-one is an isomer of pentan-3-one.

22 but-1-ene and but-2-ene are treated separately with cold, dilute acidified manganate(vii) ions.
four students, w, x, y and z, make statements about these alkenes and the diols formed from
them.

w_ one diol contains two primary alcohol groups.
x one diol contains a primary and a secondary alcohol group.
y one diol contains two secondary alcohol groups.
z__ both alkenes exhibit cis-trans isomerism.
which two students are correct?
a wandy b wandz c xandyy d xandz

23 2-bromo-2-methylpentane is a tertiary halogenoalkane.
which organic products are formed when 2-bromo-2-methylpentane reacts with a hot
concentrated ethanolic solution of sodium hydroxide?
a 2-methylpent-1-ene only
b  2-methylpent-1-ene and 2-methylpent-2-ene
c  2-methylpent-2-ene only
d  2-methylpent-2-ene and 4-methylpent-2-ene

24 poly(propene) is an addition polymer.
what are the c-c-c bond angles along its polymer chain?
a they are all 109°.
b_ half of them are 109° and half are 120°.
c_ half of them are 90° and half are 180°.
d_ they are all 120°.

29 an alcohol has the molecular formula cs5hi20. it nas several isomers.
which isomer forms a yellow precipitate with alkaline aqueous iodine?
a 2,2-dimethylpropan-1-ol
b  2-methylbutan-2-ol
c  3-methylbutan-2-ol
d _pentan-3-ol

26 when compound x is heated under reflux with aqueous sodium hydroxide solution two products
are formed: sodium ethanoate and hexan-1-ol.
what is compound x?
a b cc d
o co a o co a
o [e) o oo
oo oo

27 what is the major product z of the following reaction?
an excess of
dry hbr
————+> 7
warm
a b cc d
br br
br : br
br br
br br

238 =+|he structure of compound q is shown.
compound q
jon
o
(e)
(6)
how many chiral centres are present in a molecule of q?
a 4 b 5 cc 6 d7

30 which reaction produces an organic anion with a good yield?
a heating ethanenitrile under reflux with dilute sodium hydroxide
b heating ethanenitrile under reflux with dilute sulfuric acid
c heating ethane with sodium metal
d heating ethanol under reflux with dilute sodium hydroxide

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 which molecules have no overall dipole moment?
1 boron trifluoride
2 methane
3 phosphorus pentafluoride

33 carbon exists in several different forms. two of these forms are buckminsterfullerene and
graphene. buckminsterfullerene is a fullerene allotrope of carbon.
which statements about buckminsterfullerene and graphene are correct?
1 both have delocalised electrons.
2  buckminsterfullerene has a giant molecular structure.
3. the carbon atoms in graphene form a tetrahedral lattice.

34 carbon monoxide burns readily in oxygen to form carbon dioxide.
what does this information suggest?
1 the +4 oxidation state of carbon is more stable than the +2 state.
2 the standard enthalpy change of formation of carbon dioxide is more negative than the
standard enthalpy change of formation of carbon monoxide.
$ i sone of the equilibrium constant for the reaction, 2co(g) + o2(g) == 2co,(g), is likely
to be high.

35 the catalytic converters fitted to cars remove pollutants from the exhaust gases. some of the
reactions that occur involve oxygen, which comes from the air.
which pollutants in the exhaust gases will react with oxygen on the surface of the catalytic
converter?
1 no,
2 ~~ unburnt fuel
3 co

36 chlorine reacts with sodium hydroxide in two different ways depending upon the temperature.
reaction1 cl. + 20h + cl + clo + h20
reaction2 3clz2 + 6boh — 5cl” + clos + 3h20
which statements about these reactions are correct?
1. reaction 2 requires a higher temperature than reaction 1.
2 the products of reaction 1 show chlorine in two different oxidation states.
3. the products of reaction 2 show oxygen in two different oxidation states.

37 in which of the reactions is the organic compound oxidised by the given reagent?
1. ch3;cho + hcn reagent
2 chsch2,ch2cho + tollens’ reagent
3. chsch2cho + fehling’s reagent

38 when the apparatus is set up as shown, an orange precipitate forms in test-tube z.
v zz
air —> >
compound q + | |
acidified potassium a r 2,4-dinitrophenylhydrazine
dichromate(v1) 2 ° reagent
° o
warm
what could compound q be?
1. ch3ch2ch2oh
2 chsch(oh)ch3
3 (ch3)3coh

39 chlorofluoroalkanes that diffuse into the stratosphere are broken down by ultraviolet radiation.
radicals are generated that cause depletion of ozone.
what are these radicals?
1 chlorine radicals
2 fluorine radicals
3. alkyl radicals

40 a mixture of the three isomers of c,h2cl2 is polymerised.
which sequences will be seen within the polymer chains?
1 2 3
cl h h h cl h
tt tb $b
me te ot ha

Solve 9701_s20_qp_11