2025 DHS H1 Chem Prelim Paper 2_QP

© DHS 2025 8873/02 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H1 CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper. Additional Materials: Data Booklet 8873/02 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. Section A Answer all questions. Section B Answer one question. 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 Section A 1 11 2 9 3 11 4 10 5 14 6 5 Section B 7 / 8 20 Total 80 This document consists of 27 printed pages and 1 blank page.

2 © DHS 2025 8873/02 Section A Answer all the questions in the spaces provided. 1 (a) Use of the Data Booklet is relevant to this question. Chlorine has 25 isotopes, ranging from 28Cl to 52Cl. (i) Complete Table 1.1 to show the number of each sub-atomic particle present in an 39Cl+ ion. Table 1.1 number of protons number of electrons number of neutrons 39Cl+ [1] A sample of chlorine contains three isotopes. Data for two of the isotopes present in this sample is shown in Table 1.2. Table 1.2 mass number abundance 35 68.43% 37 21.70% The sample of chlorine has a relative atomic mass, Ar, of 35.53. (ii) Calculate the mass number of the third isotope. [2]

3 © DHS 2025 8873/02 [Turn over A beam of 35Cl+ ions is deflected in an electric field. (iii) State one similarity and one difference in the expected behaviour of a beam of 35Cl– ions in the same electric field. Briefly explain your answer. similarity ………….…………………………………………………………………... …………………………………………………………………………………………. …………………………………………………………………………………………. difference …………….……………………………………………………………..... …………………………………………………………………………………………. ……………………………………………………………………………………… [2] (b) Beryllium chloride is a simple molecule with an electron–deficient central atom. (i) Draw a ‘dot–and–cross’ diagram for the BeCl2 molecule. [1] (ii) Name the shape of the BeCl2 molecule. ……………………………………………………………………………………… [1] (iii) Deduce whether BeCl2 is a polar molecule. Explain your answer. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………… [1]

4 © DHS 2025 887