Organic Chemistry Prac Qns_ ANS

SECONDARY 4 EXPRESS – COMBINED CHEMISTRY Class Index No NAME ANSWERS 0 6 7 6 7 SCIENCE (CHEMISTRY) Topical Revision – Organic Chemistry Candidates answer on the Question Paper. Additional Materials: Periodic Table, Data Sheet 5086/5088 30 minutes Date: _______________ READ THESE INSTRUCTIONS FIRST Write your class, index number and name on ALL the work you hand in You may use a HB pencil for any drawing. Write in dark blue or black pen. Do not use staples, paper clips, glue or correction fluid. Section A – Multiple Choice Questions (5 marks) There are 5 questions in this Section. Answer ALL questions. For each question, there are four possible answers A, B, C and D . Choose the one you consider correct and write your answer in the given spaces. Each question scores 1 mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. Section B – Structured Questions (15 marks) Answer ALL questions. The number of marks is given in the brackets [ ] at the end of each question or part question. The total marks for this paper is 20 . FOR EXAMINERS’ USE Target marks Your marks Full Marks TOTAL 20 20 20 Adapted from past year prelim papers This document consists of 6 pages and 0 blank pages.

2 Section A – Multiple Choice Questions (5 marks) Write your answers in the given boxes on page 3. 1 An organic compound, X, decolourises red-brown aqueous bromine and extinguishes a lighted splint with a 'pop' sound when it reacts with magnesium. Which of the following is X? (AES 2024 Q19) A B C D 2 The structure below shows a monomer. Which of the following shows three repeating units of the polymer chain formed? (GMSS 2024 Q19) A B C D © chiasamuel 2025

3 3 Bitumen contains an organic compound with the molecular formula of C ₂₀ H ₄₂ . It undergoes a process called catalytic cracking, to form hydrocarbons with shorter carbon chains which are higher in demand. The chemical equation is given as shown: C ₂₀ H ₄₂ →2C ₆ H ₁₂ + compound K +H ₂ What is the identity of compound K ? (AMKSS 2024 Q17 - edited) A C ₄ H ₈ B C ₄ H ₁₀ C C ₈ H ₁₆ D C ₈ H ₁₈ 4 Many molecules of X combine to form a single molecule Y, as shown in the equation. n X → Y (n is a large number) Which terms best describe X and Y in this reaction? (GESS 2024 Q19) X Y A fraction monomer B monomer fraction C monomer polymer D polymer fraction 5 What reagent is used to differentiate a sample of ethanoic acid from ethanol? A A