2024 Prelims CJC H2 Chem P1 (Ans)

1 9729/01 CJC JC2 Preliminary Examination 2024 [Turn over CANDIDATE NAME CLASS 2T CHEMISTRY 9729/01 Paper 1 Multiple Choice 12 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and NRIC/FIN number on the Answer Sheet in the spaces provided. 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. This document consists of 28 printed pages. WORKED SOLUTIONS Catholic Junior College JC 2 Preliminary Examinations Higher 2

2 9729/01 CJC JC2 Preliminary Examination 2024 1 Which of the following statements about the properties associated with ionic and covalent bonds is correct? A The only covalent compounds with high melting points are those in which hydrogen bonds occur. B Any covalent compound that contains both oxygen and hydrogen in its molecule forms hydrogen bonds. C Both ionic bonds and covalent bonds cannot occur in the same compound. D Ionic compounds differ from metals in that ionic compounds do not conduct electricity in the solid state. 2 Which of the following shows the correct shape and bond angle of the molecule given? molecule shape bond angle A OF2 bent 117o B BH3 trigonal pyramidal 120o C XeF4 tetrahedral 109o D SF6 octahedral 90o Topic: Chemical Bonding The shape for each compound is as follows: 105o . ... 120o . 90o . . 90o . bent trigonal planar square planar octahedral Answer: D Topic: Chemical Bonding Option A: Incorrect, diamond and graphite has high melting points and only contain covalent bonds between the carbon atoms. Option B: Incorrect because the hydrogen atom must be directly attached to the oxygen atom for hydrogen bond to be formed. Option C: Incorrect, both ionic and covalent bonds can exist in the same compound, eg NH4+Cl-. Option D: Correct as ions in ionic compounds are in fixed positions in the solid state and hence cannot act as charge carriers in conducting electricity. Answer: D

3 9729/01 CJC JC2 Preliminary Examination 2024 [Turn over 3 Thiophenol and phenol are both acting as weak acids in aqueous solutions.