NJC H2 CHEM P1 Prelim

NJC/H2 Chem/01/2011 [Turn over   1 NATIONAL JUNIOR COLLEGE PRELIMINARY EXAMINATIONS Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9647/01 Fri 16 Sept 2011 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are 40 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 correct and record your choice in 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 paper consists of 19 printed pages and 0 blank page.

NJC/H2 Chem/01/2011 [Turn over   2 Section A For each question, there are four possible answers labelled A, B, C and D. Choose the one you consider to be correct. 1 Use of the Data Booklet is relevant to this question. The bar chart gives some information about the first ionization energies of elements numbered 1 to 4. The elements are adjacent to each other in the Periodic Table with increasing proton number either across a period from left to right, or down a group. What could these four elements be? A B, C, N, O B Co, Ni, Cu, Zn C Mg, Ca, Sr, Ba D Na, Mg, A l, Si 2 The chloride ion, Cl–, has the same electronic structure as A F– B Ne C Na+ D Ca2+ 1st I.E 1 2 3 4

NJC/H2 Chem/01/2011 [Turn over   3 3 The table gives the successive ionization energies for an element A in Period 2. 1 st 2 nd 3 th 4 th 5 th 6 th Ionization energy / kJ mol–1 950 1800 2700 4800 6000 12300 What could be the formula of the chloride of A? A ACl B ACl2 C ACl3 D ACl5 4 A mixture of 15 cm 3 of oxygen and 50 cm 3 of hydrogen is sparked continuously. What is the maximum theoretical decrease in volume? (All g ases are recorded at room temperature and pressure.) A 65 cm3 B 45 cm3 C 25 cm3 D 15 cm3

NJC/H2 Chem/01/2011 [Turn over   4   5 When the salt (C2H5)4N+Cl is treated with hydrogen chloride, a white ionic solid B is formed. When B is dissolved in water, a 20 cm 3 sample of solution requires 12 cm 3 of 0.1 mol dm 3 barium hydroxide for neutralization. Another 20 cm 3 sample of solution requires 48 cm 3 of 0.1 mol dm 3 AgNO 3 for complete precipitation of chloride as silver chloride. What do these data show the formula of the anion in B to be? A HCl2  B HCl3 2 C HCl4 3 D H2Cl3 2 6 Methane was burnt in an incorrectly adjusted burner. The methane was converted into a mixture of carbon dioxide and carbon monoxide in the ratio of 99:1, together with water vapour. What will be the volume of oxygen consumed when y cm3 of methane is burned? A 30.01(2 ) cm 2 yy  B 3(2 0.01 ) cmyy C 30.01() c m 2 yy  D 3(0 . 0 1 ) c myy

NJC/H2 Chem/01/2011 [Turn over   5 8 A group of students attempted to estimate the concentration of a solution of Fe 2+ by pipetting fixed volumes of the solution into a flask, adding an excess of dilute sulfuric acid, and then titrating with a standard solution of potassium manganate(VII) from a burette. The volume of KMnO4 solution required by one student was 0.2 cm 3 lower than that of the other students. Which of the following is a possible explanation for this discrepancy? A The last drop of Fe2+ was blown from the pipette into the titration flask. B The pipette was rinsed with water instead of the solution of Fe2+ before the titration. C The titration flask was rinsed with the solution of Fe 2+ instead of water before the titration. D The burette was rinsed with water instead of the solution of KMnO 4 before the titration. 7 Sodium thiosulfate is used in the textile industry to remove an excess of chlorine from bleaching processes by reducing it to chloride ions. 20 cm 3 of 0.10 mol dm 3 of sodium thiosulfate requires 192 cm 3 of chlorine for complete reaction at room temperature and pressure. In this reaction, which of the following is a possible formula of sulfur containing product? A HSO4  B SO2 C S D H2S 9 In which of the following pairs of compounds does the first member have a higher boiling point than the second? A PC l3 and MgCl2 B CH3NH2 and CH3F C CH3OH and CH3CH2OH D (CH3)3CCH2CH3 and CH3(CH2)4CH3

NJC/H2 Chem/01/2011 [Turn over   6 12 Which graph correctly describes the behaviour of a fixed mass of an ideal gas? (T is measured in K.) A B C D 10 Molecular dimerization can be described as the process in which two identical molecules combine to give a single product. Examples of dimers are: Al2Cl6, N2O4 and (CH3CO2H)2. Which of the following descriptions about the above dimers is incorrect?  A Hydrogen bonds hold the CH3CO2H molecules together in the dimer. B Each aluminium atom is surrounded by four chlorine atoms in Al2Cl6. C All the nitrogen-oxygen bonds in N2O4 are of equal length. D Al2Cl6 is a planar molecule. 11 Which of the following exerts the highest pressure? A 1 mol of N2 at 27oC in 2 m3 B 1 mol of O2 at 50 oC in 2 m3 C 1 mol of C4H10 at its normal boiling point D 1 mol of H2O at 50 oC in 2 dm3

NJC/H2 Chem/01/2011 [Turn over   7 13 Which is true about the signs of the enthalpy and entropy changes when a liquid boils? ∆H ∆S A + + B – + C – – D + – 14 The data below refer to gas phase reactions at constant pressure. CH3CH3 → • CH2CH3 + H• ∆Hθ = +412 kJmol–1 • CH2CH3 → CH2=CH2 + H• ∆Hθ = +618 kJmol–1 From these data, the enthalpy change ∆Hθ r for the reaction is 2 • CH2CH3 → CH2=CH2 + CH3CH3 ∆Hθ r A +1030 kJmol–1 B +206kJmol–1 C –206 kJmol–1 D –1030 kJmol–1 15 In an aluminium-air battery, one of the electrodes is a carbon rod exposed to air while the other electrode is an aluminium rod. During discharge, aluminium is converted to insoluble aluminium hydroxide at the aluminium electrode and oxygen in the air is converted to hydroxide ions at the carbon electrode. What is the mass of aluminium hydroxide precipitated if 0.030 moles of oxygen is used by the battery? A 0.51 g B 0.68 g C 2.04 g D 3.12 g

NJC/H2 Chem/01/2011 [Turn over   8   16 A sales pamphlet claims that ‘ammonium sulfate solution which is acidic, improves the growth of acid-loving rhododendron bushes by increasing both the pH of t