PJC_H1 Chemistry_2008 JC2 H1 Chemistry Prelim Paper 1 (with answers)

PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2008 H1 CHEMISTRY 8872/01 PAPER 1 18 September 2008 50 minute s Additional materials: Data Booklet Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Write your name, CT Group and index number on the answer sheet in the spaces provided unless this has already been done for you. There are thirty questions in this paper. Answer all questions. For each question, there are four possible answers labelled 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. This document consists of 11 printed pages. [Turn Over

2 Section A For each question, there are four possible answers labelled A, B, C and D . Choose the one you consider to be correct. 1 Chlorine gas is a severe irritant to the eyes and respiratory system. The maximum safe toleration level of chlorine gas in air is 0.005 mg dm-3. How many chlorine atoms are present in 500 cm3 of air at this toleration level? A 2310 65 . 35 005 . 0 × × B 2310 6 271 1 1000 005 . 0 × × × × C 2310 62 1 71 005 . 0 × × × D 2310 671 1 1000 005 . 0 × × × 2 Bones contain a complex mixture calcium salts, protein and other material. When a bone is strongly heated in a current of air, the only residue is calcium oxide. From a sample of 50.0 g of bone, 14.0 g of calcium oxide were obtained. What is the percentage by mass of calcium in the bone? A 10.0% B 14.0% C 20.1% D 23.3% 3 To identify an oxide of nitrogen, 0.10 mol of the oxide is mixed with an excess of hydrogen and passed over a catalyst at a suitable temperature. NxOy xNH3 + yH2O H2 gas catalyst The water produced weighs 7.20 g. The ammonia produced is neutralised by 200 cm3 of 1.0 mol dm-3 HCl. What is the formula of the oxide of nitrogen? A N2O C NO2 B NO D N2O4

3 4 Gaseous particle X has proton number n and a charge of +1. Gaseous particle Y has proton number (n+1). It is isoelectronic (has the same number of electrons) with X. W