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