SAJC H2 Chem 2013 Prelim P1 QP

1     [Turn Over   ST ANDREW’S JUNIOR COLLEGE JC2 Preliminary Examinations Chemistry Higher 2 9647/01 Paper 1 Multiple Choice 19 September 2013 1 hour Additional Materials: Multiple Choice Answer Sheet, Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. There are 40 questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Chose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. 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 document consists of 19 printed pages including this page. 1111

2     [Turn Over   V V PV P P Density Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 The metal, M (Ar = 52.8), combines with 1.2 g of oxygen to form the oxide M2O. The metal, M, also forms a second oxide in which the metal and oxygen are present in the ratio 14:1 by mass. What is the molecular formula of the second oxide? A M2O3 B M4O C M11O3 D M7O 2 0.0100 mol of an oxide of an element, L , represented by L 2On is found to react with exactly 8.00 x 10 -3 mol of acidified KMnO 4 solution. In the reaction, aqueous H LO4 2- ion is formed. What is the initial oxidation state of L? A + 1 B + 2 C + 3 D + 4 3 Which of the following diagrams correctly describes the behavior of a fixed mass of an ideal gas at constant T? (T is measured in K.) A C B D 1112

3     [Turn Over   4 With reference to its electronic configuration, which of the following statements is true about the electrons in the atoms of the element with atomic number 29? A The electrons in the outermost principle quantum shell experience inter-electronic repulsion. B The d electrons are in the same principle quantum shell as the outermost s electrons. C There are p electrons in 2 different principle quantum shells. D There are s electrons in 3 different principle quantum shells. 5 The graph shows the logarithm, lg, of the first eight ionisation energies of two elements in Periods 2 and 3. What is the most likely compound that will be formed between the two elements? A CO 2 B SiO2 C CS2 D SiCl4 6 Covalent bonds are formed by orbital overlap. Which of the following is not present in the following molecule?   A sp3-sp2 overlap between C1 and C2 B sp2-sp2 overlap between C2 and C3 C sp3-sp overlap between C3 and C4 D sp-sp overlap between C4 and C5 12345678 lg (ionisation energy) no. of electrons removed 1113

4     [Turn Over   7 Which of the following molecules is planar? A Benzene B SCl6 C Butanone D Cyclohexene 8 Given the following enthalpy changes: Enthalpy change of atomisation of carbon = +715 kJ mol -1 Enthalpy change of atomisation of oxygen = +248 kJ mol -1 Enthalpy change of combustion of carbon = -394 kJ mol -1 What is the bond energy of the C=O bond? A 617 kJ mol-1 B 679 kJ mol-1 C 740 kJ mol-1 D 803 kJ mol-1     9 The enthalpy changes of formation of gaseous oxides of nitrogen are positive. Which of the following statements accounts for the positive enthalpy changes? A Oxygen has a high tendency to form O2- ions. B Oxygen and nitrogen have similar electronegativity. C Nitrogen has high ionisation energies. D The nitrogen molecule has a high bond energy.     10 The equation below represents a monomer-dimer system:   kf kb 2NO2 (g) N2O4 (g) brown colourles s  Which statement about the equilibrium is correct? A kf increases and kb decreases when the equilibrium mixture is heated. B Increasing the temperature decreases the equilibrium constant Kc. C Addition of argon at constant volume shifts the equilibrium position to the right. D Addition of a catalyst will increase the colour intensity of the mixture.   ∆H < 0 1114

5     [Turn Over   11 A 1:3 molar mixture of X2 and Y2 is heated at 673 K and 100 atm of constant pressure so that it comes to equilibrium. The equilibrium mixture contains 20 % of XY3. X2 (g) + 3Y2 (g) 2XY 3 (g) Using the equation above, what is the numerical value of Kp for the reaction at 673 K? A 9.26 x 10-5 B 2.93 x 10-4 C 2.50 x 10-4 D 5.68 x 10-4     12 The numerical value of the solubility product of copper (I) iodide is 1.27×10-12. Given that HI is a strong acid, which diagram shows how the solubility product of CuI will vary with pH at constant temperature?  A C B D          Solubility product pH pH Solubility product Solubility product pH pH Solubility product 1115

13 At 2 RCO the A B C D 14 Th e 0.1 Wh max A B C D     298 K, the n O2H and R following st RCO2 - i The vo than tha A buffe 0.1 mol 0.10 mo e graph sho mol dm-3 so ich of the fo ximum buffe   Vo numerical v ’CO2H in a q tatements is is a weaker lume of 1. 0 at for R’CO2 r solution is l dm⎯3 RCO ol dm-3 of R ows the cha odium hydro ollowing cor er capacity Acid HC H2S H (COO olume of 0.1 H values for t h queous sol s true? r base than 0 mol dm -3 2 -Na+. s formed wh OH. R’COOH has ange in pH w oxide. rrectly ident occurs?  used CN SO4 F OH)2   10 mol dm-3 6 he dissocia ution are 4 R’CO2 -. H2SO4 use hen 20 cm3 s a higher p when 0.10 tifies the ac 3 acid added I ation consta .8 x 10 -6 an ed to neutr a of 0.01 mo pH than 0.10 mol dm-3 a id used and Maximu   d/ cm3 I ant of the al nd 3.6 x 10 - alize RCO2 - l dm⎯3 KOH 0 mol dm-3 cid is gradu d the point o m buffer ca I H J I J [Tu liphatic carb -3 respectiv -Na+ comple H is mixed w of aqueous ually added on the curve apacity rn Over boxylic acid ely. Which etely is lo w with 10 cm3 s R’CO2 -Na+ to 10 cm 3 e at which           ds, of wer of +. of 1116

7     [Turn Over   15 Use of the Data Booklet is relevant to this question. An electrochemical cell is set up using a Fe 3+(aq), Fe2+(aq) half–cell and a VO 2+(aq), V3+(aq) half–cell. Which of the following gives a correct effect on the Eo cell when each of the changes is made? Change Effect on Eo cell A Doubles the concentration of Fe3+ Eo cell doubles B Addition of KCN(aq) to the Fe 3+(aq), Fe2+(aq) half–cell Eo cell becomes more positive C Addition of water to the VO 2+(aq), V3+(aq) half–cell Eo cell becomes more positive D Addition of NaOH to the VO 2+(aq), V3+(aq) half–cell Eo cell becomes less positive 16 Two separate electrolyses were performed as follows, under standard conditions. 1) When concentrated hydrochloric acid was electrolysed for 10 minutes, 150 cm3 of gas were collected from the anode. 2) When aqueous copper sulfate was electrolysed for 10 minutes, x cm3 of gas were collected from the anode. If the current used in electrolysis 1 was twice the current used in electrolysis 2, what is the volume of gas that were collected in electrolysis 2? A 37.5 cm3 B 50 cm3 C 75 cm3 D 125 cm3          1117

8     [Turn Over   17 E, F and G react according to the following equation: E(aq) + 2F(aq) + G(aq)  products Two sets of separate experiments are performed in order to determine the rate equation. The results are shown: Which of the following statements is not true? A For this reaction, the rate equation is based on the overall equation. B The order of reaction with respect to [E] is zero. C The order of reaction with respect to [F] is one. D The order of reaction with respect to [G] is one. 18 Which of the following statements about the Period 3 elements is true across the period? A The melting points of the elements decrease steadily. B The electrical conductivity of the e