2021 CJC H2 CHEM Prelim P1 QP

1 9729/01 CJC JC2 Preliminary Examination 2021 CANDIDATE NAME CLASS 2T CHEMISTRY 9729/01 Paper 1 Multiple Choice September 2021 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 12 printed pages. Catholic Junior College JC 2 Preliminary Examinations Higher 2

2 9729/01 CJC JC2 Preliminary Examination 2021 1 Nitrogen exists as a diatomic molecule, N 2. Hydrazine, N2H4, and dinitrogen difluoride, N2F2, are compounds of nitrogen. Which of the following gives the correct number of  bonds in N2, N2H4 and N2F2? number of  bonds in N2 number of  bonds in N2H4 number of  bonds in N2F2 A 2 0 1 B 2 1 1 C 1 1 2 D 3 0 2 2 Aluminium chloride is a covalent compound that forms a dimer with the formula Al2Cl6. A compound of gold and chlorine has a similar molecular formula of Au2Cl6 and has the following structure: The three statements below are properties of the gold compound, Au2Cl6. 1 The oxidation state of the metal is +3. 2 The dimer exists in the vapour phase. 3 The Cl-Au-Cl bond angle is 90o. Which property described is different from that of the aluminium compound, Al2Cl6? A 1 and 2 only B 1, 2 and 3 C 3 only D 2 and 3 only

3 9729 CJC JC2 Preliminary Exam 2021 [Turn over 3 The table below lists three compounds: compound boiling point / oC CH3CH2‒S‒H 35 CH3‒S‒CH3 37 CH3CH2‒O‒H 78 Which of the following statements about the compounds is true? A The C‒S‒H bond angle is larger than the C‒O‒H bond angle because S is larger than O. B CH3CH2‒S‒H has weaker intermolecular hydrogen bonding than CH3CH2‒O‒H. C CH3CH2‒S‒H and CH 3‒S‒CH3 have similar boiling points because they have intermolecular permanent dipole – permanent dipole forces of attraction of similar strengths. D CH3CH2‒O‒H has the highest boiling point because the O‒H bond energy is higher than the S‒H bond energy. 4 Use of the Data Booklet is relevant to this question. An isotope of a metal, Z, undergoes radioactive decay to form helium and an element hafnium, Hf, according to the following equation. Z He2 4 + Hf G