TJC Prelim P1

1 9729/01/TJC Prelim/2018 [Turn Over CHEMISTRY 9729/01 Paper 1 Multiple Choice 15th September 2018 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. 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 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 13 printed pages. Write your name and Civics Group Write and shade your index number

2 9729/01/TJC Prelim/2018 [Turn Over Section A 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 (OMS). 1 Some isotopes are unstable and undergo nuclear (radioactive) reactions. In one type of reaction, an unstable nucleus assimilates an electron from an inner orbital of its electron cloud. The net effect is the conversion of a proton and an electron into a neutron. Which of the following describes this type of reaction? A 11C → 12C B 111I → 111Te C 76Br → 75Br D 76Kr → 75Br 2 Sodium hydrogencarbonate can be prepared from sodium sulfate by a three-step process: Na2SO4(s) + 4C(s) → Na2S(s) + 4CO(g) Na2S(s) + CaCO3(s) → CaS(s) + Na2CO3(s) Na2CO3(s) + H2O(l) + CO2(g) → 2NaHCO3(s) What is the mass of sodium hydrogencarbonate that could be formed from 100 kg of the sodium sulfate, assuming a 90% yield in each step? A 106 kg B 96 kg C 86 kg D 43 kg 3 Which of the following reactions is a redox reaction? A 2NO2 → N2O4 B 6HCl + As2O3 → 2AsCl3 + 3H2O C SbF3 + F2 → SbF5 D Cr2O72- + 2OH- 2CrO 42- + H2O

3 9729/01/TJC Prelim/2018 [Turn Over 4 When 2.6 g of a metal X are added to copper(II) sulfate solution 4.8 g of copper are obtained. The relative atomic mass of X is 52. Which one of the following cations of X is produced? A X4+ B X3+ C X2+ D X+ 5 20.0 cm3 of 0.02 mol dm−3 bromate(V), BrO3−, was found to react completely with 80.0 cm3 of 0.01 mol dm−3 hydroxylamine, NH2OH. BrO3− ions are reduced as follows: BrO 3– + 6e– + 6H+ → Br− + 3H2O Which of the following could be the half-equation for the oxidation of hydroxylamine? A NH2OH → ½ N2O + 2H+ + ½ H2O + 2e− B NH2OH + H2O → NO2− + 5H+ + 4e− C NH2OH → NO + 3H+ + 3e− D NH2OH + 2H2O → NO3− + 7H+ + 6e− 6 An ion ICl4n− has a square planar structure as shown below. What is the value of n? A 1 B 2 C 3 D 4

4 9729/01/TJC Prelim/2018 [Turn Over 7 Which molecule has the largest dipole? A B C D 8 Which of the following graphs correctly describes the behaviour of a fixed mass of ideal gas? A B C D 9 Phosphorus pentachloride reacts with limited amount of water to give a liquid and white fumes as shown in the equation below. PCl 5(s) + H2O(l) → POCl3(l) + 2HCl(g) HƟ = – 640 kJ mol-1 The following enthalpy changes are given: HfƟ PCl5(s) = – 444 kJ mol-1 HfƟ HCl(g) = – 92 kJ mol-1 HcƟ H2(g) = – 286 kJ mol-1 What is the standard enthalpy change of formation of POCl3(l)? A – 1278 kJ mol-1 B – 1186 kJ mol-1 C + 94 kJ mol-1 D + 274 kJ mol-1 1/p T / K constant V pV/T p / Pa V T/ oC 0 constant p 1/V p / Pa constant T

5 9729/01/TJC Prelim/2018 [Turn Over 10 Which quantity is not required in the calculation of the lattice energy of calcium hydride, CaH2,using the Born-Haber cycle? A first electron affinity of hydrogen B second electron affinity of hydrogen C first ionisation energy of calcium D second ionisation energy of calcium 11 Compound M, CH 3CH=CHCHClCH3, reacts readily with alcoholic KCN according to the following equation: CH3CH=CHCHClCH3 + CN– → CH3CH=CHCH(CN)CH3 + Cl– The following kinetics data were collected: Experiment [M] / mol dm−3 [CN–] / mol dm−3 Relative Rate 1 0.1 0.1 1 2 0.2 0.1 2 3 0.3 0.3 3 Which diagram represents the reaction profile for this reaction? A B C D energy Reaction path energy Reaction path

6 9729/01/TJC Prelim/2018 [Turn Over 12 The radioactive decay of isotopes P and Q follow first-order kinetics. Isotope P decreases from 1800 counts per minute to 450 counts per minute in six months. Isotope Q decreases from 5400 counts per minute to 1350 counts per minute in four months. In a separate experiment, a sample containing a mixture of the two isotopes was left to decay, and the molar ratio of P : Q was found to be 1 : 1 after six months. What is the molar ratio of P : Q at the beginning? A 1 : 2 B 1 : 4 C 2 : 1 D 4 : 1 13 X, Y and Z are elements in Period 3 of the Periodic Table. The following statements were made about the properties of X, Y and Z, and their compounds. 1 The oxide of Z does not dissolve in excess dilute NaOH(aq). 2 When a sample containing equimolar quantities of each oxide is mixed with water, the solution obtained is highly acidic. 3 Only the chlorides of Y and Z give an acidic solution with water. Based on the statements above, identify elements X, Y and Z. X Y Z A Na S Mg B Mg P Si C Al S Mg D Na P Si 14 Which of the following statements are true? 1 The lattice energy of magnesium oxide is more negative than the lattice energy of barium oxide. 2 The solubility product of magnesium hydroxide is smaller than that of calcium hydroxide. 3 The reducing power of strontium is weaker than that of barium. 4 Barium nitrate decompose more readily than magnesium nitrate. A 1, 2 and 3 only B 1, 3 and 4 only C 1, 2 and 4 only D 2, 3 and 4 only

7 9729/01/TJC Prelim/2018 [Turn Over 15 Astatine (At) is an element in Group 17. Which of the following statements is correct? A Silver astatide reacts with aqueous ammonia to form a soluble complex. B HAt(aq) is a weaker acid than HCl(aq). C Astatine reacts with aqueous iron(II) sulfate to form iron(III) ions and astatide. D The enthalpy change of formation of hydrogen astatide is less exothermic than that of hydrogen chloride. 16 A sample of 0.300 mol of HBr gas was decomposed in a sealed container at temperature T. The resulting equilibrium mixture was found to contain 0.015 mol of Br2. 2HBr(g) ⇌ H2(g) + Br2(g) ΔH is positive Which of the following statements are true for the reaction? 1 The mole fraction of HBr(g) is 0.27 at equilibrium 2 The equilibrium constant Kc = 3.09 x 10-3 3 The Kc will increase if reaction is carried out at higher temperature. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 17 Which statement(s) about indicators is always correct? 1 The pH working range is greater for indicators with higher pKa values. 2 The pKa value of an indicator is within its pH working range. 3 The mid-point of an indicator’s colour change