MALAYSIAN INTERNATIONAL

CHEMISTRY

OLYMPIAD (MIChO)

46th IChO (2014) Malaysian Team Selection

(Phase One)

Questions Sheet (9 pages)

30 Questions

Strictly 1.5 hours only

1. Estimate the reaction entalphy for the production of SF6(g) from SF4(g) given that the mean bond enthalpies of F2, SF4 and SF6 are +158, +343, and +327kJ mol-1, respectively at 25(C.

A.Exothermic, -434 kJ

BEndothermic, 434 kJ

C.Exothermic, -3492 kJ

D.Endothermic, 3492 kJ

2. What is the oxidation number of Mn in the permanganate ion, MnO4-?

A. 5 B. 7 C. 2 D. -2

3. The chemical names for KMnO4 and Al2O3 are?A. Potassium Manganate (IV) and Aluminium (III) Oxide

B. Potassium Manganate (VII) and Aluminium (II) Oxide

C. Potassium Manganate (VII) and Aluminium (III) Oxide

D. Potassium Manganate (IV) and Aluminium (II) Oxide

4. What is the shape of phosphorus trifluoride?A. Tetrahedron

B. Trigonal planar

C. Trigonal bypyramidal

D. None of these.

5. What is the designation for the subshell with n= 5 and l = 1?

A. 5s B. 5p C. 5d D. 5f6. Select the electronic configuration that violates the Hunds rule for an atom in its ground state.

1s 2s

2p

A.

B.

C.

D.

7. Calcium reacts with water as shown :

Ca (s) + 2H2O (l) ( Ca(OH)2 (aq) + H2(g)Given that solubility of calcium hydroxide at 0 is 2.55 x 10-4 mol/mL, how many grams of calcium hydroxide is required to dissolve in 73 L at 0? ( Atomic mass of Ca = 40.07, O = 15.99, H = 1.01)A. 58 g

B. 74 g

C. 138 g

D. 140 g

8. Which of the following species does not involve the formation of dative bonds?

A. SO42-

B. NH4+

C. NO3-

D. [Cu (NH3)4 ] 2+

9. The formula of some oxides are shown below:

Na2O MgO Al2O3 SO2 CO2

Number of each type of oxide

acidicamphotericbasic

A122

B203

C113

D212

10. The equation for the reduction of iron ore in a blast furnace is given below. How many kilograms of iron can be produced by the reaction of 7.00 kg of Fe2O3and 3.00 kg of CO?(Atomic weights: Fe = 55.85, O = 16.00, C = 12.01).

Fe2O3 + 3 CO 2 Fe + 3 CO2A. 3.65B. 4.20 C. 3.99 D. 4.74

11. What is the elemental composition of compound A?

A. C 90.00%; H 10.00%

B. C 86.62%; H 13.38%

C. C 88.16%; H 11.84%

D. C 62.44%; O10.24%; H 27.32%

12. What is the structure that corresponds to compound B?

13. What is the structure that corresponds to compound C?

14. What is the structure that corresponds to compound D?

15. What is the structure that corresponds to compound E?

16. Rank the following compounds in the order of acidity.

A: II > I > III > IV

B: II > III > I > IV

C: IV > I > III >I

D: IV > II > III > I

17. What is the relationship between the two structures below:

A. Enantiomeric

B. Diastereomeric

C. Structural Isomer

D. Identical

18. What is the major product of the reaction between 3-methy-3-pentene with Br2 in CCl4?

A. 2,2-Dibromo-2-pentane

B. 2,3-Dibromo-2-pentane

C. 2,3-Dibromo-3-pentane

D. 3,3-Dibromo-3-pentane

19. Which of the following alcohol is relatively the strongest acid in aqueous solution?

A. CH3OH

B. CH3CH2OH

C. (CH3)2CHOH

D. (CH3)3OH

20. Which is the following carbocation has the highest energy?

21. Zn (s) + 2HCl (aq) ( ZnCl2 (aq) + H2 (g)

The reaction between zinc and hydrochloric acid produces hydrogen gas. If 40mL of H2 gas is collected over water at 28oC and a barometric pressure of 750 mmHg, how many moles of HCl must have been consumed in the reaction? Given the vapour pressure of water at 28oC is 25.4mmHg.

[Gas constant = 0.08206 L atm K-1 mol-1]

A. 2.71 x 10-4 mol

B. 1.78 x 10-2 mol

C. 3.09 x 10-3 mol

D. 2.26 x 10-4 mol22. Complete combustion of gaseous hydrocarbon X produces 7.04 g of CO2 and 2.16 g of H2O. 0.56 g of the hydrocarbon occupies a volume of 256 mL, 24.8oC, and 753mmHg. Which of the following could be the plausible structural formulae of hydrocarbon X?

I. H3C-CC-CH3II. H2C=CH-CH=CH2IIICH3-CH=CH-CH=CH2

IVCH2=CH-CH2-CH=CH2[Gas constant = 0.08206 L atm K-1 mol-1, RAM of C:12, O:16, H: 1]

A. I and II

B. II and IV

C. III and IV

D. I, II, and III23. Given the standard heat of combustion of propene and propane are -2058 kJ/mol and -2219.9kJ/mol respectively. With the help of the following equation, determine the Ho for the hydrogenation of propene to propane.

4 H2 (g) + 2 O2 (g) ( 4 H2O Ho = -1143kJ/mol

A. - 104.2 kJB. - 117.4 kJC. - 96.9 kJD. - 88.6 kJ

24.Decomposition of H2O2 to H2O and O2 gas is an example of first order reaction. If the rate constant for the decomposition, k = 7.20 x 10-4 s-1, determine what is the percentage of H2O2 that has decomposed in the first 550s after the reaction begins.

A.67.3 %

B.58.7 %

C.41. 3 %

D.32.7 %

25. Formamide is a substance that is commonly used in the manufacturing of pharmaceuticals, dyes and agricultural chemicals. It decomposes at high temperature according to the following equation:

HCONH2 (g) NH3 (g) + CO (g) Kc = 4.84 at 400K

0.244 mol of formamide is allowed to come to equilibrium with NH3 and CO in a 0.52 L flask at 400K. Calculate the amount of HCONH2 present at equilibrium.

A. 0.01 mol

B. 0.12 mol

C. 0.02 mol

D. 0.25 mol26. Quantum Mechanics concerns the physics of microscopic particles. The main equation in quantum mechanics is the Schrodinger equation. One sets up the Schrodinger equation of an atom, such as the hydrogen atom and solves it to obtain the energy and wavefunction of the atom. The square of this wavefunction gives the probability density of the electron/s surrounding the nucleus of the hydrogen atom.

At pre-university chemistry level, students are exposed to the concept of atomic orbitals. For example, you should be familiar with the hydrogen 1s orbital, which is the lowest energy orbital for the hydrogen atom where one electron resides in this orbital.

This 1s orbital is obtained from the solution of the Schrodinger equation for hydrogen atom. The wavefunction of the 1s orbital is represented by the mathematical function given below;

where r is the distance of the electron from the nucleus and ao is the Bohr radius with a value of 0.529 x 10-8 cm. If we were to plot the 3D probabilitistic distribution of the electron of this 1s wavefunction, we would get the familiar looking sphere shaped distribution.

At which distance from the nucleus would the probability of finding an electron be a maximum, given that the maximum is determined by = 0 ?A. 4aoB. 3 aoC. 2 aoD. ao27. The dipole moment of a molecule describes the extent of separation of charge of a molecule. It is usually expressed in debyes (D) where 1 D = 10-18 esu.cm (electrostatic unit of charge x cm). Dipole moment is given by charge , multiplied by the separation distance d (Dipole moment = .d). For example, for HCl which has a dipole moment of 1.03 x 10-18 esu.cm and = dipole moment/d, thus, the charge the for HCl is 8.11 x 10-11 esu.

For a water molecule, the dipole moment is taken along the line separating the two hydrogen atoms (known as the C2 axis) as depicted in the diagram below. The value of this dipole moment is 1.85 D. Given the bond length of the O-H bond is 0.94 angstrom and the O-H-O angle is 105o, calculate the charge on the oxygen atom in esu.

A. 2.1 x 10-10

B. 3.2 x 10-10C. 4.1 x 10-10D. 5.2 x 10-1028. The average kinetic energy of gas molecules is related to the absolute temperature of the gas by equating it to . Calculate the root mean square speed, u, of an oxygen molecule at 18o C. [k = R/NA ; Avogadro number NA: 6.02 x 1023 molecules/mol; Gas constant R: 8.31 J/mol.K ; RAM O: 16 g/mol]

A. 4.76 x 102 m/s

B. 5.76 x 102 m/s

C. 6.76 x102 m/s

D. 7.76 x 102 m/s

29. Consider a mixture of: 1) 500 mL of 0.0100 M AgNO3; 2) 500 mL of both 0.0100 M NaCl and 0.0100 M NaBr. What is the value of [Ag+], [Cl-] and [Br-] given the Ksp of AgBr and AgCl are

5.0 x 10-13 and 1.0 x 10-10 M2 respectively?

A. 2.0 x 10-8, 5 x 10-3 and 2.5 x 10-5 M

B. 3.0 x 10-9, 5 x 10-4 and 3.5 x 10-5 M

C. 4.0 x 10-10, 5 x 10-5 and 2.5 x 10-6 M

D. 5.0 x 10-11, 5 x 10-6 and 3.5 x 10-6 M30. In a lead acid battery, the discharge reaction is Pb + PbO2 + 2H2SO4 ( 2PbSO4 + 2H2O. What is the minimum amount of Pb (in both free and compound form) needed in the battery if it were to deliver 100 A.h (ampere.hour)? Then, calculate the free energy change if the average voltage of the battery under zero load is 2V.

A. 774.18 g and -386 kJ

B. 884.17 g and -405 kJ

C. 1025.22 g and 350 kJ

D. 2011.45 g and -523 kJ

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