RJC Chemistry H2 P1 with Ans Prelims

-1- RAFFLES JUNIOR COLLEGE PRELIMINARY EXAMINATION 2008 HIGHER 2 CHEMISTRY 9746/01 Paper 1 Multiple Choice 19 September 2008 1 hour Additional Materials: Multiple Choice answer sheet Data Booklet READ THESE INSTRUCTIONS FIRST DO NOT open this question booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, Candidate Number on the Answer Sheet in the spaces provided. There are forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C, and D. Choose the one you consider to be correct and record your choice with a soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. This question booklet consists of 15 printed pages.

-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 An element Z has a second ionisation energy higher than that of the element preceding it and the element after it in the Periodic Table. What is the atomic number of Z? A 10 B 13 C 14 D 15 2 The use of the Data Booklet is relevant to this question. The pH of pure water is 7.0 at 298 K. Which of the following quantities is equal to the number of ions in 1 dm 3 of pure water at 298 K? A The number of atoms in 4.48 x 10 –6 dm 3 of C l2 at s.t.p. B The number of neutrons in 8.0 x 10 –7 g of deuterium gas, D 2 (D = 2H). C The number of molecules in 1.44 x 10 –4 g of Buckministerfullerene, C 60 . D The number of anions in 1.0 x10 –14 dm 3 of 1.0 mol dm –3 K 3[Fe(CN) 6](aq). 3 Self-igniting flares contain Mg 3P2. With water this produces diphosphane, P 2H 4, which is spontaneously flammable in air. Which equation that includes the formation of diphosphane is balanced? A Mg 3P2 + 6H 2O → 3Mg(OH) 2 + P 2H 4 B Mg 3P2 + 6H 2O → 3Mg(OH) 2 + P 2H 4 + H 2 C 2Mg 3P2 + 12H 2O → 6Mg(OH) 2 + P 2H 4 + 2PH 3 D 2Mg 3P2 + 12H 2O → 6Mg(OH) 2 + 3P 2H 4 4 Which of the following statements is correct? A XeF 4 and H 2C=C=CH 2 are planar molecules. B BC l3 and BrC l3 have the same molecular shape. C Benzene and cyclohexene are non–polar liquids. D LiA lH 4 and NaBF 4 contain dative covalent bonds. 5 Which of the following changes will have the greatest effect on the density of a fixed mass of an ideal gas? Pressure Temperature / K A doubles halves B doubles doubles C halves halves D halves constant

-3- 6 Strontium hydride is an ionic compound. The standard enthalpy changes for the following two reactions related to its constituent elements and ions are known. Sr(s) → Sr 2+ (g) + 2e – H 2(g) + 2e – → 2H –(g) What additional data is needed to determine the lattice energy of strontium hydride? A The first ionisation energy of hydrogen. B The standard enthalpy change of atomisation of hydrogen. C The standard enthalpy change of atomisation of strontium. D The standard enthalpy change of formation of strontium hydride. 7 The use of the Data Booklet is relevant to this question. Consider the energy cycle given below. (g) + 3H2(g) (g) (l)+ 3H2(g)(l) y kJ mol-1 x kJ mol-1 What is the standard enthalpy change of hydrogenation of benzene, ∆H o, in kJ mol –1? A x – y –132 B x – y –372 C y – x –132 D y – x –372 8 An increase in temperature increases the rate of a chemical reaction. For a given temperature rise, the rate will be most affected if the reaction A is exothermic. B is endothermic. C has a low activation energy. D has a high activation energy. ∆H o

-4- 9 P, Q and R react in aqueous solution according to the following equation: P + 5 Q + 6 R → 3 T + 3 U The kinetics of the above reaction was studied by the method of initial rates and the experimental results obtained are shown in the table below. Experiment Volume of 1.0 mol dm -3 P /cm 3 Volume of 1.0 mol dm -3 Q /cm 3 Volume of 1.0 mol dm -3 R /cm 3 Volume of water /cm 3 Total volume of solution /cm 3 Relative initial rate of formation of T (1) 10 50 60 80 200 1 (2) 10 25 120 45 200 2 (3) 5 25 60 10 100 4 (4) 10 25 60 5 100 8 What is the rate equation for the reaction? A Rate = k [ P][ Q] B Rate = k [ P][ Q][ R] C Rate = k [ P][ Q]2[R] D Rate = k [ P][ Q][ R]2 10 Two experiments were performed involving the following equilibrium. H 2(g) + I2(g) 2H I(g); ∆H = +54 kJ mol –1 In experiment (1) carried out at temperature T1 K, the equilibrium constant, K c = 64. In experiment (2) carried out at temperature T 2 K, 1.0 mol of H 2 and 1.0 mol of I2 were initially added into a 1 dm 3 flask. The flask was found to contain 1.2 mol of HI at equilibrium. What is the relationship between T1 and T2? A T 1 > T2 B T1 = T2 C T1 < T2 D The relationship cannot be determined.

-5- 11 Which statement concerning the equilibrium reaction given below is correct? 2CrO 4 2–(aq) + 2H +(aq) Cr 2O7 2–(aq) + H 2O( l) A A redox reaction is taking place. B The equilibrium constant, K c, has no units. C A decrease in pH will result in an increase in the concentration of Cr 2O7 2–(aq). D The addition of a catalyst will result in an increase in the concentration of Cr 2O7 2–(aq). 12 Bromocresol green is an acid-base indicator with a pH range of 3.8 to 5.4. The acidic colour of the indicator is yellow and the alkaline colour is blue. Two drops of the indicator are added to each of the four aqueous solutions listed below. Which solution has its colour not correctly stated? Solution Colour A Saturated aqueous solution of Ca(OH) 2. B Aqueous solution containing 1 mol dm –3 CH 3COOH(aq) (pK a = 4.7) and 1 mol dm -3 CH 3COONa(aq). C Dilute HC l of concentration 2.0 x 10 –5 mol dm –3. D Aqueous BaC l2 of concentration 5.0 x 10 –3 mol dm –3. 13 Some standard reduction potentials are given in the table below. Half–equation E O / V 2H 2SO 3 + 2H + + 4e– S 2O3 2– + 3H 2O E 1 [SnC l6]2– + 2e – Sn 2+ + 6C l– E 2 ½Hg 2 2+ + e – Hg( l) E 3 Sb 2O5 + 6H + + 4e – 2[Sb(OH) 2]+ + H 2O E 4 A redox reaction occurs when Sb 2O5 is mixed with S 2O3 2–, but no reaction occurs when Sb 2O5 is mixed with Hg. A solution of [SnC l6]2– has no effect on S 2O3 2–. Which of the following gives the order of the standard reduction potentials from highest to lowest? A E 2 > E 1 > E 4 > E 3 B E 2 > E 4 > E 1 > E 3 C E 3 > E 1 > E 4 > E 2 D E 3 > E 4 > E 1 > E 2 blue green yellow blue

-6- 14 Elements X, Y and Z are in Period 3 of the Periodic Table. X has the highest melting point among all the Period 3 elements. The chloride of Y has the highest boiling point among all the Period 3 chlorides. The oxide of Z has the highest melting point among all the Period 3 oxides. Which of the following statements is correct? A The first ionisation energy increases in the following order: Y < X < Z. B The electrical conductivity increases in the follo