VJC H2 CHEM P1 MCQ FINAL Prelim

 VJC 2011 9647/01/PRELIM/11 [Turn over 2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 A and B 2 react in the following way: 4A(s) + 3B2(g)  2A2B3(s) If A and B 2 are reacted together in a 2:1 mole ra tio, what is the mole fraction of A2B3 upon complete reaction? A 0.3 B 0.5 C 0.7 D 0.9 2 Naturally occurring iron consists of four isotopes, 54Fe, 56Fe, 57Fe and 58Fe. Two ions formed by the isotopes have chemical formulae shown below: 254 26Fe 256 26 Fe Which one of the following statements is true? A The electron configuration of both Fe 2+ ions is1s22s22p63s23p63d44s2. B When subjected to an electric field, 256 26 Fe ion gives a greater angle of deflection than 254 26Fe ion. C 256 26 Fe ion has more protons in its nucleus than 254 26Fe ion. D The total number of protons and electrons in each of the Fe 2+ ions is smaller than the nucleon number of the respective ion. 3 Use of the Data Booklet is relevant to this question. A gaseous mixture containing m g of N 2 and n g of CO 2 are injected into a completely evacuated container with fixed volume of 10 4 m 3 at 25°C and 1 atm. Assuming that the two gases do not reac t, which of the following gives the correct values for m and n? m n A 0.10 0.05 B 0.05 0.10 C 0.10 0.10 D 0.05 0.05

 VJC 2011 9647/01/PRELIM/11 [Turn over 3 4 Which one of the following pairs contains two species with different shapes? A NC l3 and BrCl3 B CO 3 2 and BBr3 C BeC l2 and BrCl2 – D SiF 4 and PF4 + 5 When 50 cm 3 of 1 mol dm –3 NaOH(aq) was added to 10 cm 3 of 1 mol dm –3 H2SO4(aq), a temperature rise of 5°C was obtained. Assuming that there is negligible heat lo ss to the surroundings, what is the enthalpy change of neutralization? (Density of solution may be taken as 1 g cm –3 and specific heat capacity of the solution as 4.2 J g–1K–1) A  60  4.2  5 1000 10 kJ mol1 B  60  4.2  5 10 kJ mol1 C  60  4.2  5 1000 20 kJ mol1 D  60  4.2  5 20 kJ mol1 6 At 350°C, 50% of X decomposes according to the equation: X(g) ⇌Y(g) +Z(g) If the equilibrium pressure is 1 3 p, what is the equilibrium constant, Kp for the reaction at 350°C? A 1 9 p B 1 6p C 1 3 p D p

 VJC 2011 9647/01/PRELIM/11 [Turn over 4 7 Use of the Data Booklet is relevant to this question. Hydrogen chloride can be synthesized dire ctly using a mixture of hydrogen gas and chlorine gas in a reversible reaction as shown: H2(g) + Cl2(g) ⇌ 2HCl(g) Which one of the follo wing describes the yield of hydrogen chloride at equilibrium as temperature increases? A B C D Temperature Yield Temperature Yield Temperature Yield Temperature Yield

 VJC 2011 9647/01/PRELIM/11 [Turn over 5 8 A 0.100 mol dm 3 solution of lead( II) nitrate is added, wit h stirring, into an equal volume of a solution containing a mixture of C l, Br, and I ions, each with the same concentration of 1.0 x 102 mol dm3. Given the following data: Compound Numerical value of solubility product (at 25 oC) Lead(II) chloride 1.7 x 105 Lead(II) bromide 6.6 x 106 Lead(II) iodide 9.8 x 109 Which one of the following statements is correct? A No precipitate will form. B Only PbI2 precipitate will form. C A mixture of PbI2 and PbBr2 precipitates will form. D All three precipitates, PbI2, PbBr2, and PbCl2, will form. 9 Ethyl ethanoate is formed by the r eaction between ethanol and ethanoic acid as shown below: CH 3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2O Given that the above acid-catalyzed esteri fication is first order with respect to the hydrogen ion, and assuming that all other conditions are kept constant, what is the ratio tpH 3 : tpH 1? (tpH n = time taken for the reaction conducted at pH = n to achieve 80% yield) A 0.01 B 0.33 C 3 D 100 10 Radioactive decay obeys first order ki netics. The amount of radioactivity recorded from an isotope decreased from 2720 units to 85 units in 45 hours. What is the time required for the radioactivity of the same isotope to drop from 2400 units to 300 units? A 9 hours B 18 hours C 27 hours D 36 hours H +

 VJC 2011 9647/01/PRELIM/11 [Turn over 6 11 Use of the Data Booklet is relevant to this question. The half-cells of four metals Pb, X, Y and Z were connected in pairs and the voltage was recorded. The results obtained are set out in the table below. Negative electrode Positive electrode Voltage /V Pb X 0.35 Z Pb 2.60 Y Pb 1.10 Which one of the following statements is correct? A Anions will flow from t he salt bridge to the X n+ (aq) | X(s) half-cell when it is connected to Zp+ (aq) | Z(s) half-cell. B Pb has a greater tendency than Y to form positively charged ions. C The colour of aqueous CuSO 4 solution will become lighter when Y is added to it. D Electrons will flow from electrode Y to electrode Z when the two half- cells of Zp+ (aq) | Z(s) and Ym+ (aq) | Y(s) are connected together. 12 Two electrolytic cells containing aqueous X(NO 3)m in cell 1 and molten YCln in cell 2 are connected in series. When a current was passed through the set-up, metals X and Y are produced at the cathode of cell 1 and cell 2 respectively. The volume of the gas produced at the anode of cell 1 and cell 2 is p cm3 and q cm3 respectively. What is the ratio of p : q? A 2:3 B 3:2 C 1:2 D 2:1 salt bridge Metal electrode V Metal electrode

 VJC 2011 9647/01/PRELIM/11 [Turn over 7 13 The diagram represents the first ioni sation energy of four consecutive elements in the third period of the Periodic Table, with element B showing two oxidation states in its chlorides. The sketches below represent another two properties of the elements. What are properties M and N? property M property N A third ionisation energy electronegativity B number of valence electrons boiling point C ionic radius effective nuclear charge D electrical conductivity atomic radius     proton number 0 property M     proton number 0 property N 0 A B C D     proton number First ionisation energy / kJ mol1

 VJC 2011 9647/01/PRELIM/11 [Turn over 8 A G C B ∆Hvap / kJ mol-1 D E F H Atomic number 14 The graph below shows the variation in the enthalpy change of vaporisation, ∆Hvap for 8 consecutive elements in the Periodic Table, all with atomic number ≤ 20. What can be deduced from the above graph? A E is soluble in warm benzene whereas F is not. B The chlorides become less acidic from A to C. C The pH of the solution contai ning a mixture of oxide of G and oxide of D is greater than 7. D The oxide of A reacts with excess aqueous sodium hydroxide to form a soluble complex. 15 Radium is the last element in Group II in the Periodic Table. Which one of the following is not true for radium? A It is the least reactive element in Group II. B It reacts with water to release hydrogen gas. C Its oxide is basic in water. D Its compounds conduct electricity when molten.

 VJC 2011 9647/01/PRELIM/11 [Turn over 9 16 Consider the follo wing reaction route. Which anion was present in each of the precipitates respectively? ppt A ppt C ppt D A I  SO4 2 NO 3  B Cl I NO3  C SO4 2 I Cl D SO4 2 NO3  C l 17 The table shows the electroni c configuration of five d-block elements in the Periodic Table. (The elements are represented by letters which are not their symbols.) Element Electronic configuration of the element P [Ar]3d24s2 Q [Ar]3d54s1 R [Ar]3d54s2 S [Ar]3d64s2 T [Ar]3d74s2 Which one of the following statements is incorrect? A Q2O7 2 is likely