2023 VJC H2 Chem Prelim P1 (QP)

©VJC 2023 9729/01/PRELIM/2023 [Turn Over VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 22 September 2023 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 index number, name and CT group on the Answer Sheet. There are thirty questions. 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. A Data Booklet is provided. 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 11 printed pages.

©VJC 2023 9729/01/PRELIM/2023 2 For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 In which species are the numbers of protons, neutrons and electrons all different? A Al13 27 B Cl– 17 35 C S2– 16 32 D K+ 19 39 2 Dicarbon monoxide, C 2O, is found in dust clouds in space. Analysis of it shows that the central carbon atom is sp hybridised and there are no unpaired electrons. How many lone pairs of electrons are present in a molecule of C2O? A 1 B 2 C 3 D 6 3 Which diagrams represent part of a giant molecular structure? 1 ● = C 2 ● = C 3 ● = Na ○ = Cl 4 ● = I2 A 1, 2 and 3 only C 2, 3 and 4 only B 1 and 2 only D 3 and 4 only

©VJC 2023 9729/01/Prelim/2023 [Turn Over 3 4 Three identical flasks each contains the same mass of gases E, F and G respectively. The temperature and pressure of each flask are indicated below. Gas E F G Temperature / K t t 2t Pressure / Pa p 2p p Assuming ideal gas behaviour, which of the following is a correct representation of the relative molecular masses of the three gases? A Mr(G) > Mr(F) > Mr(E) C Mr(G) > Mr(E) > Mr(F) B Mr(E) > Mr(F) > Mr(G) D Mr(F) > Mr(E) > Mr(G) 5 Which of the following explains the non-ideal behaviour of the gases present in the reaction chamber in the Haber process? A the high pressure of 150 atm B the high temperature of 450C C the presence of a catalyst D the strong bonds between the atoms in the nitrogen molecules 6 Elements X, Y and Z are in Period 3 of the Periodic Table. Element X has a chloride and an oxide where each reacts vigorously with water to form a highly acidic solution. Element Y has a low conductivity at room temperature. It forms only one chloride that hydrolyses in water forming a white solid and an acidic solution. Both the chloride and oxide of Z have high melting points. The oxide reacts readily with water. The chloride dissolves in water to form a neutral solution. What are their identities? X Y Z A Al S Na B Al S Mg C P Si Mg D P Si Na

©VJC 2023 9729/01/PRELIM/2023 4 7 P, Q and R are Group 2 elements. The three graphs below show the change in mass when 1.00 g each of P(IO3)2, Q(IO3)2 and R(IO3)2 were heated separately at a temperature of T oC. Which of the following statements about the elements P, Q, R and their compounds is correct? A The first ionisation energy of P is the most endothermic. B R reacts the most readily with water to give hydrogen gas. C Q(IO3)2 has the highest melting point. D Only oxide of P reacts with acids to form salts. 8 Due to its radioactive nature, the properties of astatine, At, has to be estimated based on its position in the Periodic Table. Which of the predictions concerning At or its compounds can be correct? A Hydrogen astatide has a higher decomposition temperature than hydrogen bromide. B When astatine reacts with sodium iodide, a brown solution will form. C Silver astatide is soluble in NH3(aq). D Astatine exists as a solid at room temperature. 9 When Tl+(aq) ions are reacted with VO3–(aq) ions, Tl3+(aq) ions and V2+(aq) ions are formed. Assuming the reaction goes to completion, how many moles of Tl+(aq) and VO3–(aq) would result in a mixture containing equal number of moles of VO 3–(aq) and V 2+(aq) once the reaction had taken place? moles of Tl+(aq) moles of VO3–(aq) A 1 2 B 1 3 C 3 2 D 3 4 P(IO3)2 R(IO3)2 Q(IO3)2 time 1.00 mass / g

©VJC 2023 9729/01/Prelim/2023 [Turn Over 5 10 Equations involving four enthalpy changes are shown. Na(g) → Na+(g) + e– ∆H = w Na(g) → Na2+(g) + 2e– ∆H = x Na(s) → Na(g) ∆H = y Na(s) → Na2+(g) + 2e– ∆H = z What is the second ionisation energy of sodium? A x B x – w C y – w D z – y 11 Which of the following changes will result in a decrease in entropy? A forward reaction of [Fe(H2O)6]2+(aq) + edta4–(aq) ⇌ [Fe(edta)]2–(aq) + 6H2O(l) B mixing of 1 mol of N2 with 1 mol of Ar at constant pressure C cooling of liquid ethanol from 50 oC to 20 oC D sublimation of iodine crystal 12 A student performed an experiment to investigate a hypothetical reaction. 2X + Y → Z The graph of [X] against time for the experiment is shown below. When the initial [ Y] doubles in another experiment , the gradient of tangent at t = 0 min increases by two times. Which of the following statements about this reaction is correct? A The unit of the rate constant is min–1. B It is a single-step reaction. C The half-life of the reaction remains unchanged when [Y] doubles. D The half-life of the reaction remains unchanged when [X] doubles. 0 2 0 4 0 0.050 [X] 0.012 5 0.025 0 time / min [Y] = 2.0 mol dm–3

©VJC 2023 9729/01/PRELIM/2023 6 13 The diagram represents the Maxwell-Boltzmann energy distribution of molecular energies at a given temperature. As temperature increases, which of the following statements are correct? 1 The proportion of molecules with energies above activation energy increases. 2 The maximum of the curve is displaced to the right. 3 At all energies, the proportion of molecules of a particular energy increases. A 1, 2 and 3 C 2 and 3 only B 1 and 2 only D 3 only 14 An equilibrium can be represented by the equation below. 2W(aq) + X(aq) ⇌ Y(aq) The equilibrium concentrations of different substances in a 0.50 dm 3 mixture are shown below. species W X Y concentration / mol dm–3 2.00 1.00 2.00 A certain amount of Y was later added to this equilibrium mixture . When equilibrium is reached again, the equilibrium concentration of X is found to be 1.20 mol dm–3. You should assume that the temperature of the mixture remained constant throughout. W