2025 H1 Chem Prelim Paper 1_HCI

This document consists of 11 printed pages and 1 blank page. © Hwa Chong Institution 2025 8873/01/Prelim [Turn over HWA CHONG INSTITUTION C2 Preliminary Examination Higher 1 CANDIDATE NAME CT GROUP 24S CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 8873/01 22 September 2025 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid or tape. Write your name and CT group in the space provided at the top of this page. 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 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 this booklet. The use of an approved scientific calculator is expected, where appropriate.

2 © Hwa Chong Institution 2025 8873/01/Prelim [Turn over 1 Use of the Data Booklet is relevant to this question. The table shows the fifth, sixth, seventh, eighth and ninth ionisation energies of an element in the third period. 5th 6th 7th 8th 9th ionisation energy / kJ mol–1 7200 8800 12 000 14 000 41 000 What element has these ionisation energy values? A P B S C Cl D Ar 2 The mineral pyrite contains sulfur and a transition metal in the fourth period. A sample of pyrite was analysed and four different atoms were identified; V, W, X and Y. The table shows information about the four types of atoms found in the sample. atom relative mass relative % abundance V 31.97 63.8 W 33.97 2.8 X 53.94 31.4 Y 55.95 2.0 What is the relative atomic mass of sulfur in the sample? A 32.05 B 32.10 C 32.97 D 39.40 3 Which row about  bonds and  bonds in hydrocarbons is correct?  bonds  bonds A can be formed by p orbitals but not s orbitals can be formed by s orbitals but not p orbitals B can be formed by s orbitals but not p orbitals can be formed by p orbitals but not s orbitals C can be formed by either s or p orbitals can be formed by p orbitals but not s orbitals D can be formed by either s or p orbitals can be formed by either s or p orbitals

3 © Hwa Chong Institution 2025 8873/01/Prelim [Turn over 4 What is the most likely bond angle at each nitrogen atom in the di-imine molecule, H–N=N–H? A 107o B 118o C 120o D 180o 5 Aluminium chloride, AlCl3, dimerises to form Al2Cl6. 2AlCl3 → Al2Cl6 Which statements are correct? 1 The geometrical arrangement of the atoms around aluminium changes from trigonal planar to tetrahedral. 2 Each aluminium atom contributes electrons to four covalent bonds. 3 There are 16 lone pairs of electrons in the Al2Cl6 molecule. A 1 and 2 only B 1 and