2025 TKGS Sec 4 Sci (Chem) Prelim Paper 1 - Answers

This document consists of 10 printed pages. TANJONG KATONG GIRLS’ SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR EXPRESS CANDIDATE NAME CLASS INDEX NUMBER SCIENCE (CHEMISTRY) 5086/01 & 5088/01 Paper 1 Multiple Choice 22 August 2025 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Write your name, index number on the Answer Sheet. There are forty questions in 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. A copy of the Data Sheet is printed on page 9. A copy of the Periodic Table is printed on page 10. The use of an approved scientific calculator is expected, where appropriate.

Tanjong Katong Girls’ School 2 Sec 4 Preliminary Examination 2025 1 A student intends to measure the rate of reaction between a volume of hydrochloric acid and a lump of zinc carbonate. ZnCO3(s) + 2HCl(aq) → ZnCl2(aq) + H2O(l) + CO2(g) Which piece of apparatus is required to perform the experiment? A distillation flask B gas syringe C test-tube D thermometer 2 Which statement explains why carbon dioxide and oxygen can be separated from air by fractional distillation? A Carbon dioxide has a larger molecular mass than oxygen. B Carbon dioxide is a triatomic molecule while oxygen is a diatomic molecule. C Carbon dioxide and oxygen have different boiling points. D Carbon dioxide is less soluble in water than oxygen. 3 An element G forms a compound with nitrogen with a chemical formula of GN. Given that G has 56 particles in the nucleus, which row shows the correct composition of an ion of G? number of protons number of neutrons number of electrons A 26 30 23 B 26 30 26 C 30 26 26 D 30 26 23 4 Which element burns in excess oxygen to form a neutral oxide? A carbon B hydrogen C magnesium D sulfur

Tanjong Katong Girls’ School 3 Sec 4 Preliminary Examination 2025 5 Helium is represented by Ne10 20 . What can be deduced about neon? A It exists as diatomic molecules. B It forms a positive ion. C It has 10 protons and 10 neutrons. D It has a nucleon mass of 30. 6 Which substance has the typical properties of a covalent compound? melting point / °C boiling point / oC electrical conductivity at room temperature A -39 361 conductor B -21 105 non-conductor C 636 1300 conductor D 3727 4829 non-conductor 7 Steel is widely used in construction because of its strength and hardness as compared to pure iron. Which statement explains why steel is used over pure iron? A Carbon atoms form covalent bonds with iron at