2025 DHS H2 Chem Prelim Paper 2_QP

© DHS 2025 9729/02 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 9729/02 18 September 2025 2 hours READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 15 2 17 3 12 4 10 5 21 Total 75 This document consists of 20 printed pages and 4 blank pages.

2 © DHS 2025 9729/02 Answer all the questions in the spaces provided. 1 (a) Fig. 1. 1 shows the relative first ionisation energies of six consecutive elements, A to F, in the Periodic Table with atomic number less than 20. The letters are not the symbols of the elements. Fig. 1.1 (i) Write an equation to represent the first ionisation energy of A. ……………………………………………………………………………………… [1] (ii) Explain why the first ionisation energy of F is more than that of E. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………… [1] (iii) Which element has the highest 4th ionisation energy? Explain your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………… [1] (iv) Element E is in Period 3. Identify element E and state the number of electron pairs in an atom of E. …………………………………………………………………………………………. ……………………………………………………………………………………… [1]

3 © DHS 2025 9729/02 [Turn over (b) 10.0 cm 3 of 0.10 mol dm −3 aqueous bromine was added to 50.00 cm 3 of a 0.10 mol dm−3 sodium hydroxide solution. The products formed were Br− and BrOx−. The excess sodium hydroxide required 15.00 cm3 of 0.20 mol dm−3 hydrochloric acid for complete neutralisation. Calculate the mole ratio between aqueous bromine and sodium hydroxide in the redox reaction. Hence write a balanced equation for the reaction and deduce the value of x. [3]

4 © DHS 2025 9729/02 (c) The halogens Cl2 and I2 both react similarly with H2S. The reaction of Cl2 with H2S is shown in equation 1. equation 1 Cl2 + H2S → 2HCl + S (i) Predict which halogen