NJC Prelim P1_Question_Paper

1 NJC SH2 Preliminary Examination 9729/01/17 NATIONAL JUNIOR COLLEGE SH2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 Thursday 14 Sept 2017 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are 30 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 paper consists of 16 printed pages.

2 NJC SH2 Preliminary Examination 9729/01/17 Instructions on how to fill in the Optical Mark Sheet Example: Shade the index number in a 5 digit format on the optical mark sheet: 2nd digit and the last 4 digits of the Registration Number. Student Examples of Registration No. Shade: 1605648 65648 SH1 CT CM G or IP B SH2 Prelim cm2P

3 NJC SH2 Preliminary Examination 9729/01/17 [Turn Over For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 A mixture of two sulfur-containing gases, H 2S and CS 2, was burned in an excess of oxygen. H2S + 3 2O2  H2O + SO2 CS2 + 3O2  CO2 + 2SO2 Upon complete combustion followed by cooling back to room temperature, the gaseous mixture was first passed through acidified KMnO4. The volume contracted by 10.0 cm3. After which, the resulting gas was passed through aqueous sodium hydroxide, a further contraction of 2.0 cm3 occurred. All volumes are measured under the same conditions. What was the mole fraction of H2S in the mixture? A 0.333 B 0.500 C 0.750 D 0.833 2 Chromium has an oxidation state of +3 in its metal ore, chromite, FeCr 2O4. Pure chromium is extracted from chromite in several steps show below. FeCr2O4 Na2CrO4 Na2Cr2O7 Cr2O3 Cr Which shows the correct type of reaction involving chromium in steps I, II and III? Step I Step II Step III A displacement acid–base displacement B oxidation oxidation reduction C displacement oxidation oxidation D oxidation acid–base redu