YJC H2 CHEM P2

READ THESE INSTRUCTIONS FIRST Write your name and CTG on all the work that you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEG E YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLL EGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE YISHUN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2014 CHEMISTRY 9647/02 HIGHER 2 Paper 2 Structured Questions 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet For Examiner’s Use Paper 1 Total / 40 Paper 2 1 / 12 2 / 23 3 / 9 4 / 10 5 / 18 Total / 72 Paper 3 Total / 80 Overall / 192 This question paper consists of 19 printed pages.

2 9647 / YJC / 2014 / Preliminary Examination / Paper 2 Answer all the questions. Planning (P) 1 Fermentation is a natural process. Man applied fermentation to make products such as wine, mead, cheese and beer long before the biochemical process was understood. In the 1850s and 1860s, Louis Pasteur became the first scientist to be known to have studied fermentation when he demonstrated fermentation was caused by living cells. The fermentation of carbohydrates into alcohol can be represented as: Sugar  alcohol + carbon dioxide This reaction is catalyzed by yeast enzymes called zymases. A balanced chemical equation for this process using table sugar or sucrose is: C12H22O11 + H2O  4CH3CH2OH + 4CO2 This type of yeast fermentation can be studied through its CO 2 production. Using the information above, you are required to write a plan to determine the rate of CO 2 production in a 30–minute fermentation process. You are provided with the following materials: - 0.100 mol dm3 sucrose solution - yeast suspension - apparatus normally found in a school laboratory (a) Write a step-by-step plan on how you would carry out this experiment. Your plan should include the following: - show how the quantity of sucrose used is calculated - all essential experimental details - a diagram of your experimental set up - a table with appropriate headings to show the data you would record when carrying out your experiment …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ……………………………………………………………………………………………

3 9647 / YJC / 2014 / Preliminary Examination / Paper 2 …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [6]

4 9647 / YJC / 2014 / Preliminary Examination / Paper 2 Alcohol produced by this fermentation is concentrated or enriched by distillation. A quantity of reaction mixture, after the fermentation process, is placed in the following set-up. (b) What is meant by distillation? …………………………………………………………………………………………… ……………………………………………………………………………………... [1] (c) Why is this simple distillation suitable for the fermentation mixture ? Give two reasons. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… ……………………………………………………………………………………… [2] (d) What is a disadvantage of this type of distiilation? …………………………………………………………………………………………… ……………………………………………………………………………………… [1] thermometer water in water out condenser receiving flask round bottom flask

5 9647 / YJC / 2014 / Preliminary Examination / Paper 2 (e) Alcohol content in a distillate is often determined by measuring its density, which depends heavily on the percentage of alcohol. A measure d density is compared with tabulated values of the density of known mixture s of alcohol and water to determine its alcohol content; typically given as a volume percentage. Most manufacturers of liquor rep ort the alcohol content by its P roof. The Proof is double the volume percentage alcohol: Proof = 2 x volume % You are provided with the data on a di stillate obtained from the distillation process: 1. Mass of sample = 97.0 g 2. Volume of sample = 100.0 cm3 3. Data of alcohol % volume versus density (g/cm3). Use these data below to determine the Proof of this sample. % by Volume Density [g/cm3] 10.0 0.98569 15.0 0.98024 20.0 0.97518 25.0 0.97008 30.0 0.96452 35.0 0.95821 40.0 0.95097 45.0 0.94277 50.0 0.93350 [2] [Total : 12]

6 9647 / YJC / 2014 / Preliminary Examination / Paper 2 2 “Hard water” is water that has high mineral content such as calcium ions. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water. A typical sample of ‘hard water’ ha