2025 YTSS Prelim 4E5N G3 Sc(Chem) P1

NAME: ( ) CLASS: YISHUN TOWN SECONDARY SCHOOL PRELIMINARY EXAMINATION 2025 SECONDARY 4 & 5 G3 SCIENCE (CHEMISTRY) (5086/1) DATE : 14 Aug 2025 DAY : Thursday DURATION : 1 hr MARKS : 20 marks ADDITIONAL MATERIALS Multiple Choice Answer Sheet (OMS) READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page. There are twenty questions. 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 very carefully the instructions on the answer sheet. INFORMATION FOR CANDIDATES 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. You may use an approved calculator. A copy of the Periodic Table and Colours of Metal Hydroxides are printed on the last two pages. This paper consists of 10 printed pages.

2 Multiple Choice Questions (20 marks) 1 Two methods of gas collection are shown below. Which row correctly describes the properties of a gas which allow it to be collected by both methods? solubility in water density A insoluble in water denser than air B insoluble in water less dense than air C soluble in water denser than air D soluble in water less dense than air 2 Food dyes, 1 and 2 are known to contain one or more of the three substances X, Y and Z. Two chromatograms are developed; one used water as the solvent, and the other used ethanol. The results are shown in the diagram below. Which statements are correct? I Substance Y is likely to be pure. II The component in Z is less soluble in water than in ethanol. III There is a component in sample 1 that is insoluble in water but soluble in ethanol. A I and II only B I and III only C II and III only D All of the above gas jar gas measuring cylinder water gas method I method II

3 3 The graph below shows how temperature changes over time when liquid S was cooled. Which statement incorrectly describes the cooling curve of liquid S? A Heat energy is gained by the particles at region XY to overcome the forces of attraction. B There is a mixture of solid and liquid at region XY. C The particles are vibrating about fixed positions at region YZ. D The particles are arranged closely in a disorderly manner at region WX. 4 Element G has an electronic structure of 2,8,1. Which statements about element G are correct? I II G reacts with cold water. G forms an ion of -1 charge. III G is in Period 3 of the Periodic Table. A I and II only B I and III only C II and III only D All of the above 5 There a