2021 SAJC Prelim P1 Question

1 ST ANDREW’S JUNIOR COLLEGE JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CLASS 2 0 S CHEMISTRY Paper 1 Multiple Choice 9729/01 16 September 2021 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. Write your name and class on the Answer Sheet in the spaces provided. 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. 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 15 printed pages.

2 1 Which of the following contains the same number of particles as 16 g of oxygen atoms? A The number of molecules in 24 dm3 of Cl2 under room conditions B The number of ions in 1 dm3 of 1 mol dm-3 aqueous HCl C The number of atoms in 111.6 g of Fe D The number of formula units of 29.25 g of NaCl 2 The first eight ionisation energies of an element Q (in kJ mol–1) are as follows: 966, 1950, 2730, 4850, 6020, 12300, 15400, 18900 Which of the following statements about element Q is correct? A It can form a basic oxide. B It can form a chloride with the formula QCl5. C It has an even number of protons in its atom. D It can form a chloride that is trigonal planar in shape. 3 A 2.0 g sample containing 0.0130 mol of organoboron compound, with the formula CxHyBOz, was burnt in an excess of oxygen. 4.58 g of CO 2 and 1.76 g of H 2O were produced. What is the molecular formula of the organoboron compound? A CH2BO2 B C8H7BO2 C C8H15BO2 D C9H15BO 4 Beams of charged particles travelling at the same speed from different sources are subjected to an electric field in two different experiments. In the first experiment, protons are deflected by an angle of +12o. In another experiment under identical conditions, particle X is deflected by an angle of 4o. What could be the composition of particle X? protons neutrons electrons A 1 2 1 B 3 3 5 C 4 5 1 D 4 5 5

3 5 Which molecule has the largest overall dipole moment? A B C D 6 Which statements about the lattice structure of the crystalline solid of diamond and ice are correct? 1 The hybridisation of the oxygen atom in ice and the carbon atom in diamond are the same. 2 The H-O-H bond angle is 105o while the C-C-C bond angle is 109.5o. 3 The lattice structure are held by strong covalent bonds only. A 1, 2 and 3 B 2 and 3 only C 1 only D 2 only

4 7 The value of pV RT is plotted against p for one mole of each of the two gases, P and Q, where p is the pressure, V is the volume and T is the temperature of the gas. Which of the following pairs of gases could be P and Q? P Q A N2 O2 B CH4 CH3Cl C HCl HF D HBr F2 8 The following reaction is thermodynamically feasible only at high temperature. C(s) + CO2(g) → 2CO(g) Which row correctly describes the signs of H and S for the reaction? H S A – – B – + C + – D + + P Q pV RT 1.0 p

5 9 Some Hc values are given below. Substance Hc / kJ mol–1 H2 (g) –285 C (s) –394 What is the ratio of heat generated by hydrogen to that of carbon if the same mass of each substance is burned? A 0.7 B 1.4 C 3.4 D 4.3 10 Some information about some of the elements of Period 5 of the Periodic Table is shown. element Rb Sr In Sn Sb Te I Xe Electrical conductivity high high high high high Semi- conductor zero zero Boiling point/ K 961 1650 2300 2540 1650 1260 457 165 Which statement about these elements is correct? A Te exists as a giant metallic structure with electrostatic forces of attraction. B TeI2 exists as an ionic compound with strong electrostatic forces of attraction. C There are more elements with metallic structures in Period 5 than in Period 3. D Those elements in Period 5 which have a boiling point under 1000 K exist as simple molecules.

6 11 The trends in two physical properties of the elements Na, Mg, Al, Si, P and S are shown in the following graphs. Which of the following illustrate s the correct physical property for the corresponding graphs above? Graph 1 Graph 2 A melting point electrical conductivity B 1st ionisation energy electrical conductivity C melting point 1st ionisation energy D 1st ionisation energy melting point 12 Use of the Data Booklet is relevant for this question. Which of the following statements is correct for Group 2 elements and its compounds? A Magnesium is kept in oil as it is more reactive while barium is kept in the open. B Barium reacts with chlorine more spontaneously than magnesium as it has a higher reducing power. C The rate of decomposition is slower for strontium carbonate than barium carbonate. D The volume of CO 2 produced is the same when the same mass of strontium carbonate and barium carbonate are decomposed. Graph 1 Graph 2

7 13 The reaction of nitrogen oxide and hydrogen involves the following steps: 2NO + H2  N2O + H2O (slow) N2O + H2  N2 + H2O (fast) Which of the following statements is incorrect based on the information above? A A redox reaction occurs in the slow step. B It is a second order reaction with respect to [NO]. C The units of the rate constant is mol3 dm9 s1. D N2O is not present in the overall equation. 14 An autocatalytic reaction is a reaction in which one of the products catalyses the reaction. Which curve would be obtained if the rate of an autocatalytic reaction is plotted against time? A B C D

8 15 Ammonia can be synthesised directly using a mixture of hydrogen gas and nitrogen gas in a reversible reaction as shown: 3H2 (g) + N2(g) ⇌ 2NH3(g) Which one of the following describes the change in yield of ammonia at equilibrium as pressure increases? A B C D 16 Which of the following mixtures are Brønsted-Lowry acid and its conjugate base pair? 1 H2O and OH– 2 H2PO4– and HPO42– 3 NaH and Na A 1, 2 and 3 only B 1 and 2 only C 2 and 3 only D 2 only

9 17 Solutions E, F, G and H contain a strong monobasic acid, a weak monobasic acid HX, a strong base and a salt of HX, but not necessarily in the same order. The concentration and pH at 25 oC for each solution are shown below. Solution Concentration /mol dm3 pH E 1.0 4.0 F 1.0 9.4 G 0.01 12.0 H 0.01 2.0 Which one of the following produces an acidic buffer? A Mixing 10 cm3 of E and 50 cm3 of G B Mixing 10 cm3 of E and 50 cm3 of H C Mixing 10 cm3 of F and 1 dm3 of H D Mixing 10 cm3 of F and 1 dm3 of G 18 How many tertiary alcohols have the molecular formula C6H14O? A 1 B 2 C 3 D 4 19 Oxidation of an alkene W gives a diol; further oxidation gives a diketone. Which one of the following could be W? A B C D

10 20 Use of the Data Booklet is relevant for this question. Which of the following temperatures and positions of substitution (relative to the substituent) is most suitable for E, F, G to form mono-nitrated products? E F G A > 55°C 2 or 4 - directing > 55°C 2 or 4 - directing > 55°C 2 or 4 - directing B > 55°C 2 or 4 - directing > 55°C 3 - directing > 55°C 2 or 4 - directing C < 55°C 2 or 4 - directing > 55°C 2 or 4 - directing > 55°C 3 - directing D < 55°C 2 or 4 - directing > 55°C 3 - dire