NYJC_H2 Chem Prelim 08 P1

NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9746/01 Paper 1 Multiple Choice 17 September 2008 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and tutor’s name on the Answer Sheet in the spaces provided unless this has been done for you. There are forty 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 you 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. This document consists of 18 printed pages and 0 blank page. [Turn over

2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider to be correct. 1 In an attempt to establish the formula of an oxide of nitrogen, a known volume of the pure gas was mixed with hydrogen and pass ed over a catalyst at a suitable temperature. 100% conversion of the ox ide to ammonia and water was shown to have taken place. N xOy xNH3 + yH2O H2(g) 2400 cm 3 of nitrogen oxide measured at room temperature and pressure produced 7.20 g of water. The ammonia produced was neutralized by 200 cm3 of 1.0 mol dm−3 of HCl. What is the oxidation number of the nitrogen in the nitrogen oxide? A +1 B +2 C +3 D +4 2 Which one of the following ions has more electrons than protons, and more protons than neutrons? [D= ] H2 1 A D − B He + C OH − D D 3O+ 3 Which one of the following molecules is planar? A NF 3 B C 2Cl4 C SF 6 D cyclohexane, C 6H12 H2 Chemistry 9746/01 NYJC J2/08 PX

3 4 Pyrogallol is a white crystalline powder and a powerful reducing agent that is used to absorb oxygen. When 30 cm3 of a gaseous hydrocarbon is exploded with 200 cm3 of oxygen, there is a contraction of 90 cm 3. On further treatment with alkaline pyrogallol, there was a reduction of 20 cm3. What is the molecular formula of t he hydrocarbon? (All volumes are measured at room temperature pressure). A C 4H8 B C 4H10 C C 3H8 D C 3H6 5 The enthalpy change when solid sodium hydroxide dissolves in water is − 44.4 kJ mol−1. 250 g of water is placed in a coffee-cup calorimeter containing 13.9 g of sodium hydroxide. If the solution has the same specific heat capacit y as liquid water, what is the rise in temperature of the solution? A 18 4 250 4 44 9 13 . . . × × K B 310 4 44 9 13 18 4 250 ×× × . . . K C 313.9 44.4 10 40 250 4.18 ×× ×× K D 18 4 9 263 10 4 44 9 133 . . . . × × × K 6 The distribution of the number of molecules with energy E is given in the sketch f