MJC H1 CHEM P1 Prelim

No part of this paper should be repro duced for commercial use without the prior written permission of Meridian Junior College. Name _______________________ Class: _______ Reg Number: _____ Meridian Junior College 2009 JC2 Preliminary Examination H1 Chemistry 8872 ©chemistry department@meridian jc [Turn over 24 September 2009 50 minutes Paper 1 Additional Material Data Booklet OMR Answer Sheet INSTRUCTION TO CANDIDATES Write your name, class and regi ster number in the spaces pr ovided at the top of this page. There are thirty questions in this section. Answer all questions. For each question, there are four possi ble answers labelled A, B, C and D. Choose the one you consider correct and record your choice in pencil on the OMR Answer Sheet. You are advised to fill in the OMR Answer Sheet as you go along; no additional time will be given for the transfer of answers once the examination has ended. Use of OMR Answer Sheet Ensure you have written your name, class register number and class on the OMR Answer Sheet. Use a 2B pencil to shade your answers on the OMR sheet; erase any mistakes cleanly. Multiple shaded answers to a question will not be accepted. For shading of class register number on the OMR sheet , please follow the given examples: If your register number is 1, then shade 01 in the index number column. If your register number is 21, then shade 21 in the index number column. This question paper consists of Pages 1 to 15.

Section A For each question, there are f our possible answers labelled A, B, C and D. Choose the one you consider to be correct. 1 Which of the following contains 4.52 × 1021 atoms? A 0.113 g of methyl free radicals, (•CH3) B 0.0319 g of ammonia C 168 cm3 of oxygen gas at standard temperature and pressure D 1.80 dm3 of chlorine gas at room temperature and pressure 2 Sodium peroxide, Na 2O2, is used in submarines for absorbing atmospheric carbon dioxide and regenerating oxygen . The reaction produces sodium carbonate as a by-product. What is the mass of Na 2O2 needed per day to absor b the carbon dioxide produced by 8 crew members in a submarine, each of whom exhales 600 dm3 of CO2 per day? [Molar volume of a gas at r.t.p. is 24 dm3 mol-1] A 0.98 kg B 1.95 kg C 7.80 kg D 15.6 kg ©chemistry department@meridian jc [Turn over 1

3 Nitrogen oxides are a major type of air pollutants. In a reaction, 0.20 mol of an oxide, N xOy was reacted with 20 dm 3 of hydrogen gas at room temperature and pressure and passed over a heated catalyst to produce ammonia and water as the only products. At the end of the reaction, 0.80 dm 3 of hydrogen gas remained. The ammonia produced requi red 0.200 mol of sulphuric acid for complete neutralisation. The reaction of the oxide with hy drogen can be represented by the following equation: N xOy (g) + 32 2 xy H2 (g)  x NH3 (g) + y H2O (l) What is the molecular formula of the oxide? A NO B NO 2 C N2O D N 2O4 4 Which of the following ions has more electrons than protons and more protons than neutrons? [ H = 1 1H; D = 2 H; T = 1 3H; C = 12 C; O =16 O ] 6 8 A CO 3 2- B H 2DO+ C OH - D TCO 3 - 5 Which of the following corresponds to t he configuration of the four electrons of highest energy for the ground state of an element in Group IV? A 1s 22s2 B 1s 22s12p1 C 2s 22p2 D 3p 4 ©chemistry department@meridian jc [Turn over 2

6 Which of the following stat ements describe a phenomenon whic h cannot be explained by hydrogen bonding? A Ice has a lower density than water at 0oC. B The boiling point of methanol is lower than that of ethanol. C Ethanal dissolves in water. D Methanoic acid molecules form dimers when dissolved in benzene. 7 Aluminium chloride catalyses certain reactions by forming a positively- charged species known as a carbocation such as CH 3 + as shown in the equation. CH3Cl + AlCl3 → CH3 + + AlCl4 - Which property makes this reaction possible? A A lCl3 is an acidic compound. B The aluminium atom in A lCl3 has an incomplete octet of electrons. C A lCl3 exists as the dimer Al2Cl6 in the vapour. D The chlorine atom in CH 3Cl has a vacant p orbital. 8 The successive ionisation energies, in kJ mol -1, of an unknown element Z are given below. 420 3100 4400 5900 8000 9600 11400 13300 Which of the follo wing statements about Z is correct? A Z is in group II of the Periodic Table. B The oxide of Z is an amphoteric oxide. C The chloride of Z hydrolyses in water to give an acidic solution. D Element Z can conduct electricity in the solid and molten state. ©chemistry department@meridian jc [Turn over 3

9 The following graph shows the firs t ionisation energy of 8 consecutive elements from A to H in the periodic table, with atomic numbers between 3 to 20. Ionisation energy B C F G A H D E Atomic number Which of the following statements is incorrect? A The chloride of E has a giant ionic structure. B The oxide of F has a giant molecular structure. C The chloride of D conducts electricity in the molten state. D Element A exists as discrete molecules at room temperature. 10 The hydrolysis of ethyl ethanoate in the pr esence of hydrochloric acid is first order with respect to ethyl ethanoate. Which diagram represents the variation of concentration of ethyl ethanoate, represented as [ester], with time? A B C D ©chemistry department@meridian jc [Turn over time [ester] [este r ] time [ester] [es ter] time time 4

11 Values of ionic product for water at different temperatures are given below: Temperature / ºC 0 25 100 Kw / mol2 dm-6 1.1 x 10-15 1.0 x 10-14 5.1 x 10-13 pH of pure water at different temperature 0 ºC 25 ºC 100 ºC A 6.5 7.0 7.9 B 7.0 7.0 7.0 C 7.5 7.0 6.1 D 15.0 14.0 12.3 12 In the diagram, curve X was obtained by observing the decomposition of 100 cm3 of 1.0 mol dm–3 hydrogen peroxide, catalysed by manganese (IV) oxide. 2H2O2(aq) → 2H2O(l) + O2(g) ΔH = -196.1 kJ mol-1 Which alteration to the original experimental conditions would produce curve Y? A Adding water. B Adding some 0.1 mol dm –3 hydrogen peroxide. C Placing the mixture in an ice-bath. D Using less manganese ( IV) oxide. ©chemistry department@meridian jc [Turn over 5

13 The enthalpy change of neutralisatio n of aqueous sodium hydroxide by hydrochloric acid is -57.2 kJ mol-1, but the enthalpy change of neutralisation of aqueous sodium hydroxide by aqueous ethanoic acid is -55.2 kJ mol-1. Which best explains the numerical difference in these values? A Aqueous ethanoic acid contains fe wer hydrogen ions than hydrochloric acid of the same concentration. ©chemistry department@meridian jc [Turn over endothermic. The process CH3CO2 3CO2 (aq) + H (aq) is exothermic. D Equal number of moles of water is produced in both reactions. 14 For the reactio NH (aq) + CO 2 3  (aq) + NH3(g) is correct? 2 B NH is the conjugate acid of NH +.  3 2. D NH4 + is the conjugate acid of NH3. 15 ic radius of the elements in Period 3 (Na to C l) changes across the period. atements does not explain the tr end of the ionic radius across the period? A Across the period, there is an increase in the nuclear charge. B The anions have greater shielding effect than the cations. ng effect among the cations. D The effective nuclear charge decreases from P3- to Cl-. B The process CH 3CO2H ( a q ) C H 3CO2 - (aq) + H + (aq) is - +C H(aq) CH n: + (aq) HCO4 3 Which of the following statements A CO3