TRIAL P1 2008

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Section AFour suggested answers labelled A, B, C, and D are given for each question. Choose one correct answer.

1 The following mass spectrum shows that element X has 2 isotopes. When X is reacted with oxygen-16, an oxide X2O3 is formed. What is the relative formula mass of X2O3?

80.1

19.9

m/e

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A 69.60B 64.40C 60.46D 72.82

. 2 The gas pressure of 2.8 g of a gaseous compound M placed in 2.5 dm3 glass vessel is

24.19 kPa. What is the relative molecular mass of M if the temperature of the gas is 37oC?

[Gas constant,R = 8.31 JK-1mol-1]

A 14.2B 119.3C 87.6D 138.4

3 The electron configuration for elements W and X are as follows.

The type and formula of the compound formed when W reacts with X is most likely to be

A ionic, WX2

B ionic, W2XC covalent, WX2

D covalent, W2X

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W: 1s2 2s2 2p6 3s2 3p5

X: 1s2 2s2 2p4

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4 Iron forms a stable chloride, FeCl3. How many fully occupied orbitals are there in the iron cation?

[Proton number of Fe = 26]

A 6B 9C 11D 12

5 Which of the following shows the correct order in the general variation of the selected physical properties when going across the third period from sodium to chlorine?

Atomic radius Electronegativity Enthalpy of vaporizationA Decreases Increases DecreasesB Decreases Increases IncreasesC Unchanged Decreases DecreasesD Increases Increases Increases

6 The successive ionization energies in kJ mol-1, of an element X are given below.

What could be the electron configuration for X?

A 1s2 2s2 2p6 3s2 3p3 B 1s2 2s2 2p6 3s2 3p6 3d3

C 1s2 2s2 2p6 3s2 3p6 3d3 4s2

D 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1

7 The molecules ICl and Br2 have almost the same relative molecular mass and molecular size. However the boiling point of ICl is about 40oC higher than that of Br2 . What is the most likely explanation for this difference ?

A There are hydrogen bonds between ICl molecules in the liquid state.B There are permanent dipole-dipole forces between ICl molecules.C The van der Waals forces in liquid ICl are stronger than in liquid Br 2.D The covalent bond in the ICl molecules is stronger than the covalent bond

in the Br2 molecules.

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1012, 1903, 2912, 4956, 6273, 21 268, 25 397

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8 The structure of a molecule of a chloride of element M is shown below. Which group in the Periodic Table is M in?

Cl

M

Cl

A Group 13B Group 15C Group 16D Group 17

9 A gaseous molecule of SeO3 does not have a dipole. Which one of the following best represents the structure of this molecule?

A

(planar, all angles 90o )B

(planar, all angles 120o )C

(pyramidal structure)D

(planar, angles of 60o and 145o)


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Cl

O O

O

Se

O O

O

Se

O O

O

Se

O

O

O

Se

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10 Which statement about the effect of a catalyst on a reversible reaction is correct?

A It increases the yield of the product in an equilibriumB It increases the equilibrium constant for the forward reactionC It increases the rate constant for both the forward reaction and the reverse reactionD It increases the rate constant for the forward reaction but not that of the reverse

reaction

11 When 3 moles of A are added to 4 moles of B in a 1dm3 container, A and B react according to the equation: A(aq) + 2B(aq) C(aq) + D(aq). The variation of the number of moles of B and C with time is given in the diagram below:-

4- Number of moles 3- 2 B 1- C 0- time / minute

Calculate Kc for the above reaction.

A 1 dm3 mol-1

B ¼ dm3 mol-1

C 1/8 dm3 mol-1

D 4 dm3 mol-1

12 Which of the following reactions at equilibrium will shift to the right when the pressure of the system is decreased at constant temperature

A N2O4(g) 2NO2(g)B N2(g) + O2(g) 2NO(g)C CO(g) + 2H2(g) CH3OH(g)D 3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g)

13 The pH of a weak monoprotic acid of concentration 0.01 mol dm-3 is 4.0. What is the pKa value for this acid?

A 4.0 B 5.0 C 6.0D 6.5


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14 Which of the underlined species in the following reactions behaves as a Lewis acid?

A H+ + OH - H2OB BCl3 + NH3 BCl3.NH3

C Br2 + FeBr3 FeBr4- + Br+

D Cl- + AlCl3 AlCl4-

15 H3A is a weak acid and has a relative molecular mass of 120. In an experiment 3.0 g of H3A was shaken with 100 m3 of benzene and 50 cm3 of water. 25.0 cm3 from the aqueous layer required 15.0 cm3 of 1.0 mol dm-3 of sodium hydroxide for neutralization. What is the partition coefficient of H3A between water and benzene?

16 The lunar module which landed the first man on the Moon in 1969 used methylhydrazine, CH3NHNH2 and dinitrogen tetraoxide, N2O4 as propellants. The equation for the reaction in the engine is

4CH3NHNH2(l) + 5N2O4(l) 4CO2(g) + 9N2(g) + 12H2O(l) [The appropriate enthalpy changes of formation are:

CH3NHNH2(l) ΔHf = + 53 kJ mol-1 ; N2O4(l) ΔHf = – 20 kJ mol-1

CO2(g) ΔHf = – 394 kJ mol-1 ; H2O(l) ΔHf = – 285 kJ mol-1 ]

What is the enthalpy change of the reaction? A [+(4 x 53) – (5 x 20)] kJB [–(4 x 53) + (5 x 20) – (4 x 394) – (12 x 285)] kJC [+(4 x 53) – (5 x 20) + (4 x 394) + (12 x 285)] kJD [+(4 x 53) – (5 x 20) – (4 x 394) – (12 x 285)] kJ

17 For which of the following ions is the enthalpy change of hydration likely to be the most exothermic?

Ion ionic radius / nm charge on ionA 0.065 +2B 0.095 +1C 0.135 +2D 0.169 +1


A 1.3B 3.0C 4.3D 4.5

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18 The diagram shows the set up of apparatus to investigate electrochemistry.

The standard electrode potentials for Ag+(ak) + e- Ag(p) and Sn2+(ak) + 2e- Sn(p) are + 0.08 V and – 0.14 V respectively.

Which of the following is true about the cell at standard conditions?A The voltmeter will show a reading of 0.04 VB Electrons will flow from electrode Ag to electrode SnC When the beaker of half-cell I is placed further away from half-cell II, the

voltmeter reading is decreased.D When the concentration of the Sn2+(aq) solution is reduced to 0.1 mol dm-3, the

voltmeter will show an increased reading.

19 A current of 8 A is passed through a molten aluminium oxide for 100 minutes using inert electrodes. Calculate the volume of gas evolves at standard temperature and pressure.[1 mol of gas occupies a volume of 22.4 dm3 at stp, Faraday’s constant = 96500 C mol-1]

A 2.8 dm3

B 5.6 dm3

C 8.4 dm3

D 11.2 dm3

20 The solubility of Group 2 sulphates decreases on descending the group. Which of the following combination is true when descending Group 2?


Hydration Energy Lattice Energy Enthalpy of SolutionA Increases Decreases More exothermicB Increases Increases More exothermicC Decreases Decreases More endothermicD Decreases Increases More endothermic

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Sn

Sn2+(aq)1 mol dm-3

Ag

Ag+(aq)1 mol dm-3

Salt bridge

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21 Which of the following will be produced when excess aqueous solution of sodium hydroxide is added into aqueous solution of Al3+ salt?

A [Al(H2O)5OH]2+

B [Al(H2O)4 (OH)2]+

C [Al(H2O)3 (OH)3]D [Al(H2O)2 (OH)4]-

22 Which of the following statements explains aluminium oxide is insoluble in water but able to react with acid and base?

A Aluminium oxide is amphoteric.B Aluminium oxide have partial covalent character.C Aluminium oxide have high lattice energy.D Aluminium oxide can form complexes .

23 Most of the chemical properties of aluminium metal are caused by the high polarising power of the Al3+ ion. Which of the following properties of aluminium compounds cannot be explained by the high polarising power of the Al3+ ion?

A The Al3+ ion can form complexes.B Aluminium chloride is a covalent compound.C A solution containing [Al(H2O)6]3+ ions is acidic.D The lattice energy of aluminium fluoride is very high.

24 Which of the following is correct regarding dinitrogen tetraoxide, N2O4?

A It is polarB It has a ‘V’ shapeC It is produced from NO2

D It contains one unpaired electron

25 Why is hydrogen iodide a stronger acid than hydrogen chloride?

A A molecule of hydrogen chloride is more polar than a molecule of hydrogen iodide

B The enthalpy change of formation of hydrogen iodide is greater than that of hydrogen chloride

C The covalent bond in the hydrogen iodide molecule is weaker than that in the hydrogen chloride molecule

D The dissociation of hydrogen chloride molecules is suppressed by stronger dipole-dipole interactions.


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26 When chlorine is passed into aqueous sodium hydroxide at room temperature and the mixture is then heated, the products formed are At room temperature After heating

A Cl- ClO-

B Cl- and ClO- Cl- and ClO3-

C Cl- ClO- and ClO3-

D Cl- and ClO- ClO3-

27 A compound of chromium with the general formula, CrCl3.6H2O, dissolves in water to form an aqueous solution. When this solution is treated with excess aqueous silver nitrate, only one third of the total chlorine present is precipitated as silver chloride.Which of the following is the formula of the ionic species present in the original chromium compound?

A Cr3+

B [Cr(H2O)6]3+

C [Cr(H2O)5Cl]2+

D [Cr(H2O)4Cl2]+

28 The rate of reaction between methane and chlorine in the presence of sunlight at 140°C is reduced by the addition of NO2 to the reacting mixture. Which of the following best explains this observation?

A NO2 breaks the C-H bond in methaneB NO2 decreases the number of chlorine free radicals.C NO2 prevents the formation of the chlorine free radicalsD NO2 prevents the collision between the chlorine free radicals and the methane

molecules

29 Which of the following statements is true regarding benzene?

A Benzene is odourlessB Benzene is a gas at room temperatureC Benzene undergoes nucleophilic addition reactionD Benzene burns in excess of oxygen to produce carbon dioxide and water

30 Which of the following pairs is correct regarding the type of bond and the type of mechanism in alkenes?

Type of bond Reaction mechanismA Single Free radical additionB Single Electrophilic additionC Double Electrophilic addition


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D Double Free radical addition

31 Arrange the following haloalkanes in the order of increasing reactivity towards SN1 reaction.

I CH3Cl II CH3CH2Cl, III CH3CHClCH3

IV CH3C(CH3)ClCH3

A I, II, III, IVB II, I, III, IVC III, II, IV, ID IV, III, II, I

32 The major product formed when 2-iodobutane is heated with ethanolic sodium hydroxide is

A CH3CH2CH2CH2OHB CH3CH=CHCH3

C CH3CH2CH=CH2

D CH3CH2CH2CH2O-Na+

33 Of the following methods, which one cannot be used to differentiate between ethanal and propanone?

A Iodoform test B Tollens reagentC Fehling solution D Mass spectrometer

34 When propanal reacts with Tollen’s reagent, what are the principal inorganic and organic products?

A Ag and CH3CH2COOH B Ag2O and CH3CH2COOH C Ag and CH3CH2CH2COOHD AgNO3 and CH3CH2COOH

35 Which of the following compounds (i) can react with phosphorus pentachloride to form white fumes of hydrogen chloride (ii) can be reduced to primary alcohol?

A CH3COCH3

B C6H5COOHC (CH3)3COH


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D CH3COOC6H5

36 When ethanoyl chloride is added to phenylamine, C6H5NH2, at room temperature, the organic product obtained is

A C6H5NHCH3

B C6H5N(CH3)2

C C6H5NHCOCH3

D CH3COC6H4NH2

37 An organic compound, P, undergoes a nucleophilic substitution reaction with aqueous

ammonia to form the organic compound, Q. When Q is hydrolysed, ethanoic acid is obtained. Compound P is most likely to be

A CH3COClB CH3CH2Br C CH3CONH2

D CH3CH2COOCH3

38 Some aminoethanoic acid (glycine) is dissolved in a buffer solution of pH 9.0. Which of the following gives the structures of the two main forms of aminoethanoic acid at this pH?

A +NH3CH2COO- and NH2CH2COO-

B NH2CH2COOH and NH2CH2COO-

C +NH3CH2COOH and NH2CH2COO-

D +NH3CH2COOH and NH2CH2COOH

39 The monomer for both types of rubber obtained from the Hevea brasiliensis tree and the Tsonandra gutta rubber tree is 2-methylbuta-1,3-diene. What is the similarity between these polymer chains?

A DensityB Hydrogenation productC Dipole momentD Melting point

40 Arrange the following compounds in order of increasing acid strength.

I CH3OH II CH3CH(OH)CH3

III IV

A I, II, III, IVB II, I, III, IV


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CH2OHOH

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C III, IV, II, ID IV, II, I, III

Section BFor each of the questions in this section one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct. The responses A to D should be selected on the basis of the following.

A B C D1 only is correct. 1 and 2 only are

correct.2 and 3 only are

correct.1, 2, and 3 are

correct.

41 Which of the following assumptions is/are made concerning the formation of metallic bonds?

1 The metal crystal consists of a lattice of positively charged ions.2 The overlapping of atomic valence shells forms a negatively charged sea of

mobile electrons.3 The strength of metallic bonds depends on the number of valence electrons that

can be delocalized.

42 Which of the following statements is/are true when solid ammonium chloride is added to aqueous ammonia solution?

1 the value of Kb decreases2 the pH of the solution decreases 3 the degree of dissociation of ammonia decreases

43 The diagram below shows the boiling point-composition curve for aqueous methanoic acid system. Which of the following statements about aqueous methanoic acid is/are true?

Boiling point / oC

0% % methanoic acid 100%

1 Aqueous methanoic acid shows negative deviation from Raoult’s law.2 A 50% aqueous methanoic acid when fractionally distilled produces aqueous

methanoic acid containing 77% of methanoic acid as the second distillate.3 Intermolecular forces between the different molecules in the mixture are weaker

than the intermolecular forces between the molecules in the pure liquids


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77%

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correct.

44 The standard electrode potentials of a few half-cells are given below:Electrode Reaction Eθ / V

Ti3+ + e- Ti2+ – 0.37 Fe3+ + e- Fe2+ +0.77HNO2 + H+ + e- NO + H2O +0.99VO2+ + 2H+ + e- V3+ + H2O +0.34

Which of the following will oxidise V3+ to VO2+ under standard conditions?

1 Ti3+

2 Fe3+

3 aqueous HNO2

45 The diagram shows the Born-Haber cycle for the formation of X2O3 from its elements under standard conditions.

Which of the following statements is/are correct?

1 ΔH3 is the enthalpy change of atomisation of X2 ΔH4 is the total ionisation energy of X3 The enthalpy change of atomisation of oxygen is +495.0 kJ mol-1


Energy

2X3+(g) + 3O2–(g)

2X3+(g) + 3O(g)ΔH5 = +1950.0 kJ

2X(g) + 3O(g)ΔH4

2X(s) + 3O(g) ΔH3 = +831.0 kJ

2X(s) + 3/2 O2(g) ΔH2 =+742.5 kJ

X2O3(s)ΔH1 = – 1117.1 kJ

ΔH6 = Lattice energy

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correct.

46 Which of the following oxides is/are amphoteric?

1 SiO2 2 GeO2

3 PbO2

47 Freons are used as refrigerants because

1 they are odourless2 they are chemically inert3 they are easily liquefied by pressure

48 In the reaction between a ketone and HCN catalysed by NaCN, which of the following statements about the reaction mechanism is/are true?

1 A new carbon-carbon bond is formed2 In the intermediate, the oxygen atom carries a negative charge3 The last stage involves the formation of a hydrogen-oxygen bond

49 Amino acid is highly soluble in water compared to other organic compounds. This is because

1 the compound is amphoteric in nature2 the compound has a carboxyl group and an amino group3 the compound can form hydrogen bonds with water molecules

50 Part of the structure of a polymer is shown below.

-NHCO(CH2)4CO2(CH2)2NHCO(CH2)4CO2(CH2)2-

Which of the following statements about this polymer is/are correct?

1 It is both a polyamide and polyester2 It would undergo alkaline hydrolysis3 It could be made from ClCO(CH2)4COCl and HOCH2CH2NH2


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ANSWER TRIAL EXAM CHEMISTRY PAPER 1 2008

NO ANSWER NO ANSWER1 A 26 B2 B 27 D3 D 28 B4 B 29 D5 A 30 C6 A 31 A7 C 32 B8 D 33 A9 B 34 A10 C 35 B11 C 36 C12 A 37 A13 C 38 A14 D 39 B15 A 40 D16 B 41 D17 A 42 C18 D 43 B19 A 44 C20 C 45 B21 D 46 C22 B 47 D23 D 48 D24 C 49 C25 C 50 D


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TRIAL P1 2008

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