MJC H2 Chem 2012 Prelim P3 QP

Class Reg Number Candidate Name _____________________________ MERIDIAN JUNIOR COLLEGE Preliminary Exam Higher 2 ___________________________________________________________________ H2 Chemistry 9647/3 Paper 3 Free Response 18 Sep 2012 2 hours Additional Materials: Data Booklet Writing paper ___________________________________________________________________ INSTRUCTIONS TO CANDIDATES Write your name, class and register number in the spaces provided at the top of this page. Answer 4 out of 5 questions in this paper. Begin each question on a fresh page of writing paper. Fasten the writing papers behind the given Cover Page for Questions 1 & 2 and Cover Page for Questions 3, 4 & 5 respectively. Hand in Questions 1 & 2 and 3, 4 & 5 separately. You are advised to spend about 30 min per question only. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. You are reminded of the need for good English and clear presentation in your answers. ___________________________________________________________________ This document consists of 14 printed pages (including the cover pages) copyright chem dept @ meridian jc

copyright chem dept @ meridian jc Answer any 4 out of 5 questions in this paper. Begin each question on a fresh sheet of writing paper. 1 Sugars, or saccharides, are the most abundant bio- molecules found on the planet and play many important biological roles. A simple sugar , a derivative of a straight chain polyhydroxyl alcohol and glycerol , is considered to be the parent of all sugars. (a) 2-chloropropane-1,3-diol can be synthesised from glycerol via the reaction scheme below. Suggest reagents and conditions for steps I to III, and draw the structural formula of intermediates A and B. [5] CH2-CH-CH2 OH OH OH KMnO4, dilute H2SO4 heat CH2-CH-CH2 OH OH Cl Step III H2O Step I A Step II B C-CH-C O O Cl OHHO glycerol 2-chloropropane-1,3-diol HOOC C O COOH

copyright chem dept @ meridian jc (b) Glucose, an important simple sugar or monosaccharide, is required by the cells in our body as a source of energy and metabolic intermediate. A common source of glucose is sucrose or table sugar. In humans and other mammals, sucrose is broken down into its constituent monosaccharides , glucose and fructose as shown below. sucrose glucose fructose (i) Name the functional group, other than ether (R -O-R), present in sucrose. (ii) Suggest the type of reaction undergone by sucrose. [2] (c) Glucose undergoes complete combustion to form carbon dioxide and water. (i) Write a balanced equation for the complete combustion of glucose. (ii) The standard enthalpy change of formation of CO 2, H2O and glucose is -394 kJ mol-1, -286 kJ mol-1 and -1275 kJ mol-1 respectively. Use your answer in (c)(i) and the data given to calculate t