2024 RI H1Chem Prelims P1 Questions

RAFFLES INSTITUTION 2024 YEAR 6 PRELIMINARY EXAMINATION Higher 1 CHEMISTRY 8873 / 01 Paper 1 Multiple Choice 19 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not open this question booklet until you are told to do so. Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions in this section. 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 the question booklet. The use of an approved scientific calculator is expected where appropriate. This document consists of 12 printed pages.

2 © Raffles Institution 2024 8873/01/S/24 [Turn Over For each question, there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which statement about one mole of ethanal, CH3CHO, is correct? A It contains 6.02 x 1023 atoms. B It contains 6.02 x 1023 carbon atoms. C It contains 1.81 x 1024 hydrogen atoms. D It contains 6.02 x 1023 molecules. 2 The charge on an electron is −1.60 x 10–19 coulombs. Aluminium reacts with fluorine to form aluminium fluoride, AlF3. Calculate the charge removed from one mole of aluminium atoms as they form one mole of aluminium fluoride, AlF3. A −2.89 x 105 C C −4.80 x 10−19 C B −9.63 x 104 C D −1.81 x 1024 C 3 The manganate(VII) ion, MnO 4−, is a strong oxidi sing agent in acidic solution. It oxidises iodide ions, copper(I) ions and sulfite ions, SO32−. The relevant half-equations are given. MnO4− + 8H+ + 5e− ⇌ Mn2+ + 4H2O I2 + 2e– ⇌ 2I− Cu2+ + e– ⇌ Cu+ SO42− + 2H+ + 2e− ⇌ SO32− + H2O Which statements about the reactions of 1 mole of MnO4−(aq) are correct? 1 It reacts with 5 moles of copper(I) ions, producing 5 moles of copper(II) ions. 2 It reacts with an excess of iodide ions, producing 5 moles of iodine molecules. 3 It reacts with 2.5 moles of sulfate ions, producing 2.5 moles of sulfite ions. A 1 only C 1 and 3 only B 1 and 2 only D 1, 2 and 3

3 © Raffles Institution 2024 8873/01/S/24 [Turn Over 4 Use of the Data Booklet is relevant to this question. The table shows the number of subatomic particles in different atoms or ions. number of neutrons number of protons number of electrons W 12 12 10 X 13 12 12 Y 16 15 18 Z 18 17 18 Which statement about W, X, Y and Z is correct? A W has a charge of 2−. B Z is an isotope of Y. C W and Y form W2Y3. D WZ2 has a giant ionic lattice structure. 5 The ninth to thirteenth ionisation energies of an element, G, in kJ mol −1 are shown. The atomic number of G is less than 20. ionisation energies / kJ mol−1 9th 10th 11th 12th 13th 33 878 38 726 42 321 46 485 148 231 Which statement about G is correct? A G is a Period 2 element. B G is likely to form a chloride with the formula GCl2. C G is likely to form a chloride with the formula GCl4. D G forms a chloride with a giant molecular structure. 6 Which molecule is non-polar? A SF4 B CH2Br2 C NF3 D SiCl4

4 © Raffles Institution 2024 8873/01/S/24 [Turn Over 7 Which equation shows a reaction in which a co -ordinate (dative covalent) bond is formed, resulting in a trigonal pyramidal shape about the central atom(s)? A H2O + H+ ⎯→ H3O+ B NH3 + BF3 ⎯→ NH3•BF3 C Al2Cl6 ⎯→ 2AlCl3 D N2 + 3H2 ⎯→ 2NH3 8 The table shows the boiling points of various substances. substance boiling point / C Br2 59 NH3 −33 H2O 100 Which statements explain the differences in the boiling points? 1 Br2 has a larger electron cloud size than NH3. 2 H2O has a larger electron cloud size than NH3. 3 The hydrogen bonds in H2O are more extensive than in NH3. A 1 and 2 only C 1 and 3 only B 2 and 3 only D 1, 2 and 3 9 AIBN is a common reagent used for the initiation of radical reactions. AIBN Which statement about AIBN is correct? A It is linear about both N atoms in the N=N bond. B It contains 4 lone pairs of electrons. C It is tetrahedral about all carbons in AIBN. D It contains 5  bonds and 11  bonds.

5 © Raffles Institution 2024 8873/01/S/24 [Turn Over 10 Which change is endothermic? A H2O(l) ⎯→ H2O(g) B H2O(l) ⎯→ H2O(s) C 2H(g) + O(g) ⎯→ H2O(g) D 2C2H6(g) + 7O2(g) ⎯→ 4CO2(g) + 6H2O(g) 11 When 50.0 cm 3 of 2.0 mol dm –3 sulfuric acid was added to 100.0 cm 3 of 1.5 mol dm –3 sodium hydroxide solution, the temperature rose by 12.6 C. Assume that the density and the specific heat capacity of the final mixture are 1.0 g cm–3 and 4.2 J g–1 K–1 respectively. What is the enthalpy change of neutralisation for the above reaction? A –1200 kJ mol–1 B –79.4 kJ mol–1 C –52.9 kJ mol–1 D –17.6 kJ mol–1 12 The table shows the enthalpy changes of formation, ∆Hf, of some compounds. compound ∆Hf / kJ mol−1 SO2(g) –297 H2S(g) –20 H2O(l) –286 H2S undergoes combustion according to the following equation. 2H2S(g) + 3O2(g) ⎯→ 2SO2(g) + 2H2O(l) What is the standard enthalpy change of combustion of H2S? A +563 kJ mol–1 B +1126 kJ mol–1 C –563 kJ mol–1 D –1126 kJ mol–1

6 © Raffles Institution 2024 8873/01/S/24 [Turn Over 13 A compound, P, decomposes by a first order reaction. At the start of the reaction, the concentration of P is 0.300 mol dm –3. After 900 s, the concentration of P falls to 0.0375 mol dm–3. What is the total time taken for the concentration of P to fall to 0.01875 mol dm–3? A 1200 s B 1350 s C 1500 s D 1800 s 14 X and Y were reacted in two separate experiments, where the concentration of Y was varied from 1.0 mol dm−3 to 2.0 mol dm−3. The following graph was obtained. What is the rate equation for the reaction? A rate = k [X]2 B rate = k [Y] C rate = k [Y]2 D rate = k [X][Y]2

7 © Raffles Institution 2024 8873/01/S/24 [Turn Over 15 Nitrogen monoxide is oxidised to form nitrogen dioxide. O2 + 2NO ⎯→ 2NO2 The following results were obtained from the investigation of the kinetics of the reaction. experiment initial [O2] / mol dm–3 initial [NO] / mol dm–3 initial rate / mol dm–3 min–1 1 1.2 0.6 8.0 2 0.6 0.6 4.0 3 2.4 1.2 64.0 What is the rate equation for the reaction? A rate = k [O2][NO] B rate = k [O2][NO]2 C rate = k [O2]2[NO] D rate = k [O2][NO]4 16 Which statement is always correct when the system is at equilibrium? P + Q ⇌ R + S A The rate of the forward and reverse reactions are equal. B The concentration of the reactants and products are equal. C The rate constant of the forward and reverse reactions are equal. D The rate of both the forward and the reverse reactions are equal to zero. Commented [JTW1]: Added “always”

8 © Raffles Institution 2024 8873/01/S/24 [Turn Over 17 2.0 mol of H2(g) was mixed with 1.0 mol of CO(g) and equilibrium was established at a given temperature. 2H2(g) + CO(g) ⇌ CH3OH(g) initial amount / mol 2.0 1.0 0