2020 JPJC Prelim Paper 1

 Jurong Pioneer Junior College [Turn Over NAME CLASS 19S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2020 CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice 24 September 2020 1 hour Candidates answer on separate paper. 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, class and exam index number 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 or 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 12 printed pages.

2  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2020 1 When 20 cm 3 of a gaseous hydrocarbon was completely burnt in 130 cm 3 of oxygen, the volume of gas remaining a fter the reaction was 100 cm 3. This volume was decreased to 40 cm 3 when the resulting mixture was passed through aqueous NaOH. All measurements were made at room temperature and pressure. What is the formula of this hydrocarbon? A C2H2 B C3H6 C C3H8 D C4H10 2 25.0 cm3 of 0.05 mol dm 3 KClO4(aq) required 50.0 cm 3 of 0.20 mol dm 3 TiCl3 (aq) to reach the end-point. Given that titanium(III) is oxidised to titanium( IV) in this reaction, which of the following formulae correctly represents the reduction product of the ClO4 ion? A Cl B ClO2 C ClO3 D OCl 3 Alpha particles, 4 2 He2+, are commonly emitted by larger radioactive nuclei during radioactive decay. The diagram below shows the path of a mixture of a charged species X, 7 3 Li+ and alpha particles after passing through an electric field. Which of the following statements are true? 1 X could be an electron. 2 Plate Y is positive. 3 The angle of deflection of alpha particles is 3.5 times of the angle of deflection of Li+. A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 Source

3  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2019 [Turn Over 4 Which element has the largest atomic radius? A Br B In C K D Rb 5 In which of the following pairs does the second compound have a higher boiling point than the first? A P4 Cl2 B CaO Na2O C CH3OH CH3ONa D CH3CH2OH CH3CH2SH 6 Which of the following pairs of species have the same shape? A PCl3 BF3 B NO2+ NO2 C BeCl2 NH2− D SO32− NH3 7 Which of the following pairs contain molecules that are both polar? Molecule I Molecule II A C2H5Cl CHCl3 B CCl4 CFCl3 C CHCl3 C2Cl4 D C2H5Cl C2Cl4

4  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2020 8 Which graph is obtained when pV is plotted against p for a fixed amount of an ideal gas at constant temperature? A pV p B pV p C pV p D pV p 9 The values of some ∆H terms for anhydrous MgCl2 are given in the table below. lattice energy of MgCl2 −2526 kJ mol−1 enthalpy change of hydration of Mg2+ −1890 kJ mol−1 enthalpy change of hydration of Cl− −384 kJ mol−1 What is the enthalpy change of solution of anhydrous MgCl2, in kJ mol−1? A +132 B +252 C −132 D +5184 10 The decomposition of hydrogen peroxide in aqueous solution is a first order process. lf 10 % of the hydrogen peroxide in a solution of concentration 0.1 mol dm 3 decomposes in 5 minutes at a certain temperature, what percentage of the hydrogen peroxide in a solution of concentration 0.2 mol dm3 would decompose in 5 minutes at the same temperature? A 5 % B 10 % C 19 % D 20 %

5  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2019 [Turn Over 11 The rate of the decomposition of the diazonium cation, C6H5N2+ + H2O  C6H5OH + H+ + N2 can be followed by measuring the time taken for the same volume of N2 to be produced from a range of diazonium cation concentrations. To find the order of the reaction with respect to th e diazonium cation, which would be the most suitable graph to plot using the data? A [C6H5N2+] against 1/time B [C6H5N2+] against time C volume of N2 against 1/time D volume of N2 against time 12 The following equation represents the conversion of Y2 to Y. Y2(g) ⇌ 2Y(g) The conversion was studied using a fixed amount of Y2 in a reaction vessel. At different times during the experiment, changes were made to the conditions in the reaction vessel. The change in the concentrations in the equilibrium mixture with time is given by the graph below: Which one of the following statements is correct? A A catalyst was added at T1. B There was a decrease in volume of the reaction vessel at T2. C There was an increase in temperature at T2. D More Y2 was introduced at T2.

6  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2020 13 The graphs below show the variation of the percentage of gaseous products present at equilibrium, with temperature and pressure. Which one of the following systems could the graphs represent? A N2(g) + 3H2(g) ⇌ 2NH3(g) H = –92 kJ mol1 B 3O2(g) + 4NH3(g) ⇌ 2N2(g) + 6H2O(g) H = –1248 kJ mol1 C 2N2(g) + O2(g) ⇌ 2N2O (g) H = +82 kJ mol1 D CO2(g) + C(s) ⇌ 2CO (g) H = +173 kJ mol1 14 Which of the following statements about acids, bases and salts is correct? A 10 cm3 of 1.0 mol dm-3 of NaOH reacts with 5 cm3 of 1.0 mol dm-3 CH3CO2H to produce an alkaline buffer. B 10 cm 3 of 1.0 mol dm -3 of NH3 reacts with 5 cm 3 of 1.0 mol dm -3 HCl to produce an alkaline buffer. C 1.0 mol dm-3 of aqueous CH3CO2Na has lower pH than 1.0 mol dm-3 of aqueous NH4Cl. D 1.0 mol dm-3 of CH3CO2H has higher pH than 1.0 mol dm-3 of aqueous CH3CO2Na. 15 A sample of waste solution at pH 1 is found t o contain 0.100 mol dm 3 zinc(II) nitrate and 0.100 mol dm3 lead(II) nitrate. Solid sodium hydroxide is slowly added until the pH is 5. The solubility product of zinc( II) hydroxide is 3.00 x 10 17 mol3 dm-9 and that of lead(II) hydroxide is 1.42 x 10-20 mol3 dm-9. Which statement describes what happens in the solution? A No precipitate is formed. B Only lead(II) hydroxide is precipitated. C Only zinc(II) hydroxide is precipitated. D Both zinc(II) hydroxide and lead(II) hydroxide are precipitated. pressure % products at equilibrium (T + 10) oC T oC

7  Jurong Pioneer Junior College 9729/01/J2 PRELIMINARY EXAM/2019 [Turn Over 16 Use of the Data Booklet is relevant to this question. The standard reduction potentials of some vanadium species are tabulated below. half-reaction Eo / V V2+(aq) + 2e– V(s) –1.20 V3+(aq) + e– V2+(aq) –0.26 VO2+(aq) + 2H+(aq) + e– V3+(aq) + H2O(l) +0.34 Which of the following metal(s), when added in excess, will reduce VO2+ to V3+? A Sn only B Sn & Zn C Sn & Pb D Zn & Pb 17 Which of the following explain why an aqueous solution of aluminium chloride is acidic? 1 Cl– ions react with water to form hydrochloric acid. 2 Aluminium ions have a high charge density. 3 The H–O bonds are weaker in [Al(H2O)6]3+ than in H2O. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only 18 Element A, which is from Period 3, has the highest fourth ionisation energy among all the elements in Period 3. A student came up with the statements below t o descri