IJC_2008_H2 Chemistry_Prelim II_Paper2

INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATIONS 2 in preparation for General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY Paper 2 Structured Candidates answer on the Question Paper Additional Materials: Data Booklet 9746/02 15 September 2008 1 hour 30 min READ THESE INSTRUCTIONS FIRST Write your index number, name and civics group on all the work you hand in. Write in dark blue or black pen. You may use pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. For Examiner’s Use Section A 1 13 2 11 3 8 4 12 5 16 Significant Figures Handwriting Total 60 Answer all questions in the space provided. A Data Booklet is provided. You are advised to show all working in calculations. You are reminded of the need for good English and clear presentation in your answers. You are reminded of the need for good handwriting. Your final answers should be in 3 significant figures. You may use a calculator. The number of marks is given in brackets [ ] at the end of each question or part question. At the end of the examination, fasten all your work securely together. This document consists of 15 printed pages and 1 blank page. [Turn overInnova Junior College

2 © INNOVA 2008 9746/02 [Turn over For Examiner’s Use Answer ALL questions on the space provided 1 Aspirin, or acetylsalicylic acid is used as an anti-inflammatory medication. It has been established that low doses of aspirin may be given immediately after a heart attack to reduce the risk of another heart attack or of the death of cardiac tissue. Aspirin has the structural formula: (a) Paracetamol and aspirin are commonly used for the relief of fever, headaches, and other minor aches and pains. Median lethal dose, LD50 of a toxic substance or radiation is the dose required to kill half the members of a tested population. LD 50 figures are frequently used as a general indicator of a substance's acute toxicity. The LD 50 of Aspirin is 1100 mg kg –1 of body mass and of paracetamol is 338 mg kg–1of body mass. (i) Suggest and explain whether aspirin or paracetamol is more toxic. ……………………………………………………………………………....……….... ……………………………………………………………………………....……….... (ii) Calculate the minimum number of 325 mg aspirin tablets that will be toxic to a 50 kg person. [2]

3 © INNOVA 2008 9746/02 [Turn over For Examiner’s Use (b) The synthesis of aspirin is classified as an esterification reaction, where the alcohol group from the salicylic acid reacts with an aci