NYJC Prelim CHEM P1 ANS

1 NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 1 CHEMISTRY 8872/01 Paper 1 Multiple Choice 25 September 2009 50 mins Additional Materials: Mult iple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and tutor’s name on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty 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 you 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 document consists of 14 printed pages. [Turn over H1 Chemistry 8872/01 NYJC J2/09 Prelims

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 How many cations are present in 0.5 moles of sodium carbonate? A 0.5 B 1.0 C 3.01 x 10 23 D 6.02 x 1023 2 Ammonium nitrate can be produced by reaction between nitric acid and ammonia as shown below. If the yield of the reaction is 65 %, determine the volume of 5.0 mol dm –3 nitric acid required to r eact with ammonia (excess) to form 20 kg of ammonium nitrate. HNO3 + NH3  NH4NO3 A 32.5 dm3 B 50 dm3 C 77 dm3 D 385 dm3 3 When potassium chlorate(V), KClO 3, is heated at its melting point, it disproportionates to potassium chlorate(VII), KClO4, and potassium chloride. What is the maximum number of moles of potassium chlorate(VII) which can be produced from 0.1 mol potassium chlorate(V)? A 0.1 B 0.08 C 0.075 D 0.06 H1 Chemistry 8872/01 NYJC J2/09 Prelims

3 4 The use of the Data Booklet is relevant to thi s question. Which of the species contains 18 neutrons and 18 electrons? A 33P2– B 33S2– C 33P3– D 33S3– 5 Ga, Ge, As and Se are successive elements in Period 4. Which of the following statements is true? A Ga2+ and Ni are isoelectronic. B Both Se and Ge have two unpaired electrons at ground state. C First ionisation energy of Se is greater than that of As as the effective nuclear charge increases across the period. D As has only three unpaired electrons, thus the highest fluoride formed is AsF3. 6 A solution of ammonia in water contains A simple molecules only. B simple molecules and hydrogen bonded molecules only . C simple molecules, hydrogen bonded molecules and ions. D ions only. 7 Which one of the following pairs do the molecules hav e similar shapes? A AlCl3 and PCl3 B BF3 and NH3 C BeCl2 and H2O D AlCl3 and BCl3 H1 Chemistry 8872/01 NYJC J2/09 Prelims

4 8 The boiling point of 2,2-dimethylpropane is lower than that of pentane because A 2,2-dimethylpropane is not polar whereas pentane is polar. B a molecule of 2,2-dimethylpropane has more electrons than a mole cule of pentane. C a molecule of 2,2-dimethylpropane has less surface area of contact with other molecules than those of pentane and thus experiences weaker induced dipole-dipole attraction. D molecules of 2,2-dimethylpropane do not form hydrogen bond but those of pentane do. 9 Given the following enthalpy changes: ─214 kJ mol-1 I2 (g) + 3 Cl2 (g) 2ICl3 (s) +38 kJ mol-1 ΔH I2 (s) + 3 Cl2 (g) What is the standard enthalpy change of formation of solid iodine trichloride, ICl 3? A +176 kJ mol-1 B +138 kJ mol-1 C -88 kJ mol-1 D -138 kJ mol-1 H1 Chemistry 8872/01 NYJC J2/09 Prelims

5 10 A student used the apparatus below to determine the molar heat of combustion of propanol. The following results were obtained: Mass of 1-propanol burnt = 0.60 g Mass of water heated = 200 g Initial temperature of water = 21.0°C The enthalpy of combustion of 1-propanol is –2021 kJ mol−1. Assuming no heat loss, what would be the final temperature of the wate r? The use of the Data Booklet is relevant to this question. A 24.2°C B 29.1°C C 45.2°C D 48.4°C H1 Chemistry 8872/01 NYJC J2/09 Prelims

6 11 Consider the following equilibrium reaction in a closed vessel: CaCO3(s) CaO(s) + CO 2(g) ΔH = +178 kJ mol1 At 800oC, the equilibrium constant is 0.236 atm. Which one of the following statements is TRUE about the equilibrium? A The position of the equilibrium shifts to the right when temperature is decreased. B The position of the equilibrium shifts to the right when pressure is decreased. C The value of the equilibrium constant decreases with increasing temperature. D The value of the equilibrium constant decreases when less CaCO3 is used. 12 ic equation that represents the reaction of ro 3 + D HCl + HCO3 ─  Cl─ + H2CO3 13 ion formed by mixing equal volumes of two uti f pH 2.0 and 4.0? D 3.3 The biological fluid that maintains blood pH is blood plasma. It is composed of H2CO3(aq) and HCO3 ─(aq). The ion hyd chloric acid with this buffer i s A HCl + H2CO3  Cl─ + H3CO3 + B H3O+ + HCO3 ─  H2O + H2CO3 C H3O+ + H2CO3  H2O + H3CO What is the final pH of a solut sol ons o A 2.0 B 2.3 C 3.0 H1 Chemistry 8872/01 NYJC J2/09 Prelims

7 14 The kinetic s of the reaction between H+(aq) and S2O3 2-(aq) can be investigate experimentally by varying the volumes of HCl(aq) and Na2S2O3(aq) used and determining the time taken, t, for the formation of sulphur to completely obscure the cross as shown in the diagram. S2O3 2-(aq) + 2H+(aq) → S(s) + SO2(g) + H2O(l) The table below shows the experimental results obtained. Volume used / cm3 Experiment 1.0 mol dm-3 HCl(aq) 0.040 mol dm-3 Na2S2O3(aq) H2O(l) t / s 1 10.0 5.0 25.0 170 2 15.0 5.0 20.0 170 3 15.0 10.0 15.0 85 4 20.0 20.0 0.0 x What is the value of x in Experiment 4? A 21 B 43 C 85 D 170 beaker HCl(aq) + Na2S2O3(aq) cross 15 What is observed when magnesium chloride is added to water? Solubility in water pH of resulting solution A Dissolves 2 B Dissolves 6.5 C Insoluble 7 D Very slightly soluble 8 H1 Chemistry 8872/01 NYJC J2/09 Prelims

8 16 In which of the following pairs is the r adius of the second atom greater than that of the first atom? A Na, Mg B Sr, Ca C P, N D Cl, Br 17 Consider the sequence of oxides Na2O, SiO2, P4O10. Which factor decreases from Na2O to SiO2 and also from SiO2 to P4O10? A covalent character B melting point C pH when mixed with water D solubility in aqueous alkali 18 Which reagent and conditions are used to bring about the reaction from methylbenzene to 4-chloromethylbenzene? A Chlorine in the dark B Chlorine with aluminium chloride C Chlorine with uv light D Concentrated hydrochloric acid heated under reflux H1 Chemistry 8872/01 NYJC J2/09 Prelims

9 19 In the given apparatus set-up, compound X is found to give a green solution in test-tube A and an orange precipitate in test-tube B. A B heat air pump 2,4 dinitrophenylhydrazine reagent Compound X + acidified potassium dichromate (VI) Which of the following is likely to be compound X? A CH3CH2CH2CH2OH B CH3CH(OH)CH2CH3 C (CH