MI Prelim H2 Chem P1 QP ans_for exchange

Class Adm No Candidate Name: This question paper consists of 12 printed pages and 2 blank pages. 2025 Preliminary Examination Pre-University 3 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 17 Sep 2025 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet 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 Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice 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 question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks) H

2 1 Sulfur dioxide is a preservative that can be found in small amount in wines. The sulfur dioxide content in wine can be determined through back titration. A 25 cm3 sample of wine is reacted with 30.0 cm3 of 0.01 mol dm−3 of excess aqueous iodine, oxidising the sulfur dioxide in the wine to sulfate, SO42−, in the process. SO2 + I2 + 2H2O ⟶ SO42− + 4H+ + 2I− The unreacted iodine requires exactly 2 4.80 cm 3 of 0.02 mol dm −3 sodium thiosulfate for complete reaction. 2S2O32− + I2 ⟶ 2I− + S4O62− What is the concentration of sulfur dioxide, in mol dm−3, in the wine? A 2.08  10−3 B 2.48  10−3 C 9.92  10−3 D 2.77  10−2 2 Which of the following contains approximately the same number of the stated particles as there are atoms in 18.0 g of water? 1 number of ions in 142.1 g of sodium sulfate, Na2SO4 2 number of molecules in 6.0 g of hydrogen gas 3 number of neutrons in 6.0 g of carbon-12 A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 3 Ions of the two most common isotopes of zinc are shown below: Zn30 64 2+ Zn30 66 2+ Which of the following statements is correct? A Both these Zn2+ ions have the same number of electrons but different number of protons. B Both these Zn2+ ions have the same electronic configuration 1s22s22p63s23p63d84s2. C The Zn30 64 2+ ion has fewer neutrons in its nucleus than the Zn30 66 2+ ion. D The Zn30 66 2+ ion will be deflected more than the Zn30 64 2+ ion in an electric field of the same strength.

3 [Turn over 4 The successive ionisation energies (IE) of two elements, W and X, are given below. IE / kJ mol−1 1st 2nd 3rd 4th 5th 6th 7th 8th W 1090 2350 4610 6