2021 C1 Promo P1 QP

This question booklet consists of 9 printed pages. HWA CHONG INSTITUTION C1 Promotional Examination Higher 2 CANDIDATE NAME CT GROUP 21S CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 30 September 2021 40 min READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Complete the information on the Multiple Choice Answer Sheet as shown below. There are twenty 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.

2 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over A, M 1 Which particle does not contain either an unpaired s electron or an unpaired p electron? 1 Cr 2 Ge 3 S2 4 Sc 1 (h) A 4 only B 1 and 2 only C 3 and 4 only D 1, 3 and 4 only B, M 2 Use of the Data Booklet is relevant to this question. A scientist attempts to produce C14 using a neutron and an isotope X of an element as shown in the equation below. one neutron + X  C14 + H3 Which row in the table correctly states the number of neutrons in X and the identity of X? 1 (d) number of neutrons in X identity of X A 3 Li B 7 Li C 9 N D 14 N

3 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over B, H 3 The graph shows the successive ionisation energies for the removal of the first 19 electrons from an element Y. Which statement about Y may be correct? 1(j) A Y is cobalt. B Y is manganese. C Y belongs to Group 14. D Y belongs to Group 17. A, L 4 A compound has the structure shown. What are the values of the bond angles x, y and z? 2(e) x y z A 109.5 90 180 B 109.5 109.5 120 C 120 90 180 D 120 109.5 120 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 energy / kJ mol1 no. of electrons removed

4 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over A, L 5 When barium metal burns in oxygen, the ionic compound barium peroxide, BaO2, is formed. Which dot-and-cross diagram could represent the structure of the peroxide anion in BaO2? 2(b)(i) A B C D B, M 6 In which pairs of compounds does the first molecule have a net dipole but the second molecule have no net dipole? 1 SO2 and CO2 2 PF3 and BF3 3 BrF5 and SiF4 5 (e)(ii) A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only B, H 7 Flask A contains 1 dm3 of helium at a pressure of 2 kPa, flask B contains 2 dm3 of argon at a pressure of 4 kPa and flask C contains 4 dm3 of water vapour at a pressure of 2 kPa. The temperature is measured to be 110 C. If the flasks are connected and the temperature is now decreased to 40 C, what is the final pressure? 3(d) A 0.5 kPa B 0.9 kPa C 1.2 kPa D 2.1 kPa B, M 8 In an experiment, H 2S reacted with BrO 3– in a 5:2 ratio to form elemental sulfur and a bromine-containing product. The reaction was carried out under acidic conditions. What is the oxidation state of Br in the bromine-containing product? 6(h) A 0 B –1 C +1 D +3

5 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over B, M 9 When a 10 cm3 sample of hydrocarbon was completely burnt in 100 cm3 of oxygen, the final gaseous mixture which contained carbon dioxide and unreacted oxygen was found to have a volume of 75 cm 3. This final volume of gas was treated with an excess of aqueous potassium hydroxide and a further reduction of 40 cm3 was observed. All gas volumes were measured at the same temperature and pressure. What is the formula of the hydrocarbon? 6g(ii) A C2H4 B C2H6 C C4H8 D C4H10 B, M 10 Forward osmosis is a process that uses a semi -permeable membrane to effect the separation of water via a natural osmotic pressure gradient, without applying an external pressure. A common application involves concentrating fruit juice as shown in the diagram below. The semi-permeable membrane only allows small molecules such as water through, but retains all other molecules and ions. The enthalpy change for the forward osmosis process is very small, and can be considered as being zero. What are the correct signs of ∆S and ∆G for the forward osmosis process? 7(i), (k) S G A – – B + – C – + D + + Diluted Fruit Juice Concentrated Fruit Juice Saline Water (slightly diluted) Saline Water (highly concentrated salt water) semi-permeable membrane

6 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over B, L 11 In an experiment to measure the enthalpy change of solution of MgC l2, a 2.00 g sample of the solid (Mr = 95.3) was dissolved completely in 100 cm3 deionised water. The temperature rose by 7.5 C. Assuming that the specific heat capacity of water is 4.2 J g–1 K–1, what is the enthalpy change of solution of MgCl2 in J mol–1? 7(d) A − 102 × 4.2 × (7.5 + 273) 2.00 ÷ 95.3 B − 100 × 4.2 × (7.5 + 273) 2.00 ÷ 95.3 C − 102 × 4.2 × 7.5 2.00 ÷ 95.3 D − 100 × 4.2 × 7.5 2.00 ÷ 95.3 A, L 12 Nitramide undergoes acid-catalysed decomposition according to the following equation. H+(aq) H2NNO2(aq) H2O(l) + N2O(g) nitramide Which method is not suitable for studying the kinetics of this reaction? 8(e) A Measuring the change in [H+(aq)] over time. B Measuring the change in total mass of the reaction mixture over time. C Connecting the reaction flask to a gas syringe and tracking the change in gas syringe reading over time. D Connecting the reaction flask to a manometer and tracking the change in manometer reading over time. B, H 13 The table below shows some experimental results obtained for the reaction between 1-bromopropane (RBr) and sodium hydroxide. expt volume of 0.010 mol dm3 RBr / cm3 volume of 0.50 mol dm3 NaOH / cm3 volume of deionised water / cm3 total volume of reaction mixture / cm3 rate of reaction / mol dm3 min1 1 10.0 40.0 0.0 50.0 3.0  105 2 5.0 10.0 10.0 25.0 1.5  105 3 20.0 4.0 26.0 50.0 x Given that the order of reaction with respect to RBr is one, and t he half -life of RBr in experiment 1 is t min, which statement is correct? 8(b)(i), 8(d), 8(c)(i) A The order of reaction with respect to NaOH is zero. B The new half-life of RBr in experiment 3 is 10t min. C The value of the rate constant is 6.0  103. D The value of x is 6.0  105.

7 © Hwa Chong Institution 2021 9729/01/C1 Promotional Exam 2021 [Turn over B, M 8(a), 8(b)(iii) 14 Hydrogen reacts with gaseous bromine to form hydrogen bromide, H2(g) + Br2(g)  2HBr(g) and with gaseous iodine to form hydrogen iodide. H2(g) + I2(g)  2HI(g) For the first reaction, the rate equation is rate = k1[H2][Br2]1.5 [Br2] + k2[HBr] For the second reaction, the rate equation is rate = k[H2][I2] What can be deduced by the above information only? 1 Only the hydrogen/iodine reaction could be a single step reaction. 2 The mechanism of the hydrogen/bromine reaction involves free radicals. 3 The rate of formation of HI is twice the rate of consumption of I2. 4 For the hydrogen/bromine reaction, the formation of HBr slows down the rate of the forward reaction. 8(b)(iii), 8(