JJC H2 Chem 2012 Prelim P1 QP

Jurong Junior College 9647/01/Prelim 2012 [Turn Over JURONG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9647/01 Paper 1 Multiple Choice 13 September 2012 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. Write your name, class and shade your exam index number on the Answer Sheet in the spaces provided. There are forty questions on this paper. Answer all questions. For each que stion 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. A Data Booklet is provided. Do not write anything on the Data Booklet. This document consists of 16 printed pages.

2 Jurong Junior College 9647/01/Prelim 2012 [Turn Over SECTION A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1. Use of the Data Booklet is relevant to this question. When x mol of cobalt is added to a solution containing y mol of cobalt(III) ions, cobalt (II) ions are formed in the resultant solution. In the resultant solution, the number of moles of cobalt(II) ions are three times that of cobalt(III) ions. Hence, which of the following are possible values of x and y? x y A 1 2 B 1 3 C 1 5 D 2 3 2. In an experiment, a sample of gadolinium element was vaporised, ionised and passed through an electric field. Analysis of the deflection occurring at the electric field region revealed the following data for a beam of 157Gd+. What would be the angle of deflection for a sample of doubly charged strontium ions? A 0.6° B 3.6° C 7.2° D 16.5° 3. In which pair of molecules is the strength of intermolecular forces of I greater than that of II? I II A CH3CH2CH2F CH3CH2CHF2 B trans CH3CCl=CClCH3 cis CH3CCl=CClCH3 C CH4 H2O D CH3CH2COOH CH3CH2CH2OH 2 o 157Gd+ Source  +

3 Jurong Junior College 9647/01/Prelim 2012 [Turn Over 4. The equation below represents the reaction of gaseous atoms of non -metal Y and of hydrogen to form gaseous Y2H6 molecules. 2Y(g) + 6H(g)  Y2H6(g) H = –2775 kJ mol1 The bond energy of an HY bond is 395 kJ mol1. What is the bond energy of a YY bond? A –405.0 kJ mol1 B –202.5 kJ mol1 C +202.5 kJ mol1 D +405.0 kJ mol1 5. Hydrogen peroxide slowly decomposes into water and oxygen. 2H2O2(l)  2H2O(l) + O2(g) Given that the standard enthalpy change of formation of H 2O2(l) is –188 kJ mol –1 and standard enthalpy change of formation of H 2O(l) is –286 kJ mol –1, calculate the enthalpy change of this decomposition. A −98 kJ mol–1 B −196 kJ mol–1 C +98 kJ mol–1 D +300 kJ mol–1 6. Nitrosyl chloride, NOCl, decomposes on heating according to the equation below: NOCl(g) ⇌ NO(g) + ½ Cl2(g) When 100 cm 3 of nitrosyl chloride was placed in a closed container at constant pressure and heated to a co nstant temperature, it was found that nitrogen monoxide constitutes 40% of the equilibrium mixture. What is the total volume of gases in the equilibrium mixture at the temperature of the reaction? A 100 cm3 B 125 cm3 C 150 cm3 D 167 cm3

4 Jurong Junior College 9647/01/Prelim 2012 [Turn Over 7. The equilibrium constant for the reaction represented by the following equation is smaller than 1.0. Which of the following gives the correct relative strengths of the acids and bases in the reaction? HPO4 2−(aq) + H2BO3 −(aq) ⇌ H2PO4 − (aq) + HBO3 2− (aq) Acids Bases A H2PO4 − > H 2BO3 − and HBO3 2− > HPO 4 2− B H2BO3 − > H 2PO4 − and HBO3 2− > HPO 4 2− C H2PO4 − > HPO4 2− and HBO3 2− > H2BO3 − D H2BO3 − > HPO4 2− and H2PO4 − > HBO3 2− 8. A sparingly soluble barium salt dissociates in solution according to the equation: BaL2(s) ⇌ Ba2+(aq) + 2L−(aq) If the solubilit y product of Ba L2 is q mol3 dm−9, what is the concentration of L− at equilibrium in a saturated solution of BaL2? A 3 q B 3 1      4 q C 3 1 q D (2q) 3 1 9. A commercial pharmaceutical drug X has a constant half–life of 2.0 hours. The drug will lose its effectiveness in the human body once its mass falls below 40 mg. Given that a patient was prescribed with 320 mg tablet form of drug X, how often should he take his prescription in order to maintain the effectiveness of drug in his body? A every 2.0 hours C every 6.0 hours B every 4.0 hours D every 8.0 hours 10. The reaction of hydrogen peroxide with iodide ions in an acidic solution is first order with respect to hydrogen peroxide as well as iodide ions, and zero order with respect to hydrogen ions.

5 Jurong Junior College 9647/01/Prelim 2012 [Turn Over H2O2(aq) + 2H+(aq) + 2I (aq)  2H2O(l) + I2(aq) Two experiments were carried out. Which pair of diagram s represents the variation of [H2O2] and [H+] with time? Experiment 1: In the presence of excess I  Experiment 2: In the presence of excess I  and H2O2 A B C D 11. The standard electrode potentials of Ag +|Ag, Zn2+|Zn and Cu 2+|Cu are +0.80 V, 0.76 V and +0.34 V respectively. Which of the following conclusions can be drawn from these data? A Silver is less electropositive than copper. B Silver displaces zinc from a solution containing zinc ions. C Zinc ion has a greater tendency to be reduced than copper ion. D Zinc has a lower tendency than silver to form positively charged ions. [H2O2] time0 [H+] time0 [H+] time0 [H2O2] time0 [H+] time0 [H2O2] time0 [H+] time0 [H2O2] time0

6 Jurong Junior College 9647/01/Prelim 2012 [Turn Over 12. Four metals Pb, x, y and z, were connected in pairs as shown in the diagram below and the voltage was recorded. The results obtained are recorded in the table below. Negative terminal Positive terminal Voltage (V) Pb x 0.35 y Pb 1.10 z Pb 2.60 Which set shows an increase in the reducing power of the metals? weakest strongest A z y Pb x B x y Pb z C Pb x y z D x Pb y z 13. Which property of Group II elements (beryllium to barium) decreases with increasing atomic number? A reactivity with water B solubility of hydroxides C second ionisation energy D thermal stability of the carbonates 14. The element astatine lies below iodine in Group VII of the Periodic Table. Which one of the following properties is correct for astatine? A It forms diatomic molecules which dissociate less readily than chlorine molecules. B It reacts explosively with hydrogen. C It can oxidise iodide to iodine. D It exists as a crystalline solid. Metal electrodeMetal electrode V salt bridge

7 Jurong Junior College 9647/01/Prelim 2012 [Turn Over 15. The following graph shows the first ionisation energies of eight consecutive elements J to R, which have atomic numbers between 3 to 20 in the Periodic Table. M R Q P N J K L Atomic Number 1st Ionisation Energy/ kJ mol-1 Which one of the following statements about the elements is false? A R has the highest melting point. B The ionic radius of J is larger than the ionic radius of K. C Q forms a insoluble hydroxide which dissolves in excess dilute NaOH(aq). D Oxide of P gives a higher pH than oxide of N when reacted with water. 16. A chromium compound dissolves in water to give a green solution E which undergoes the following reactions. Which of the following statements is incorrect? A The reaction of E to form F is a ligand displacement reaction. B The complex ion in F is more stable than that in E. C The yellow solution G contains Cr2O7 2 ions. D The reaction of G to H is an acid-base reaction. 17. Use of the Data Booklet is relevant to this question. E green solution F purple solution NH3(aq) G yellow solution H2O2(aq) H+(aq) H orange solution

8 Jurong Junior College 9647/01/Prelim 2012 [Turn Over Which of the following is true about the first row transition metals or its compounds? 18. In black and white photographic film, light converts silver chloride into metallic silver. After the