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chemistry_sl_p3_2 - c 1 hour IB DIPLOMA PROGRAMME PROGRAMME...

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Unformatted text preview: c 1 hour IB DIPLOMA PROGRAMME PROGRAMME DU DIPLÔME DU BI PROGRAMA DEL DIPLOMA DEL BI M03/420/S(3) CHEMISTRY STANDARD LEVEL PAPER 3 Thursday 15 May 2003 (morning) Candidate number INSTRUCTIONS TO CANDIDATES Write your candidate number in the box above. Do not open this examination paper until instructed to do so. Answer all of the questions from two of the Options in the spaces provided. You may continue your answers on answer sheets. Write your candidate number on each answer sheet, and attach them to this examination paper using the tag provided. At the end of the examination, indicate the letters of the Options answered in the candidate box on your cover sheet and indicate the number of answer sheets used in the appropriate box on your cover sheet. 223-163 18 pages –2– Option A – Higher physical organic chemistry M03/420/S(3) A1. The compounds with the molecular formula C4 H 9 Br all undergo nucleophilic substitution reactions when warmed with sodium hydroxide solution. The equation for each of the reactions is C4 H 9 Br + OH → C4 H 9OH + Br − − When the reaction of one of these compounds was investigated the following kinetic data were obtained. Experiment number 1 2 3 (a) Initial [C4 H 9Br] / mol dm −3 0.010 0.020 0.020 Initial [OH – ] / mol dm −3 0.010 0.010 0.020 Initial rate of reaction / mol dm −3 min −1 2.0 × 10−3 4.0 × 10−3 4.0 × 10−3 Explain the term nucleophilic substitution. ......................................................................... ......................................................................... ......................................................................... [2] (b) Deduce the order of reaction with respect to C4 H 9 Br . ......................................................................... [1] (c) − Deduce the order of reaction with respect to OH and explain your answer. [2] ......................................................................... ......................................................................... ......................................................................... ......................................................................... (d) State the rate expression for the reaction. ......................................................................... (e) Calculate the value of the rate constant for the reaction and state its units. ......................................................................... ......................................................................... ......................................................................... ......................................................................... (This question continues on the following page) 223-163 [1] [2] –3– (Question A1 continued) (f) Give the equations for the mechanism of this reaction. M03/420/S(3) [2] (g) Define the term rate-determining step and identify this step in the mechanism. ......................................................................... ......................................................................... ......................................................................... [2] (h) Define the term molecularity and deduce its value in the mechanism. ......................................................................... ......................................................................... ......................................................................... [2] 223-163 Turn over –4– M03/420/S(3) A2. Propanoic acid, CH3CH 2COOH, is a weak acid. (a) Give the equation for the ionization of propanoic acid in water and deduce the expression for the ionization constant, K a , of propanoic acid. ......................................................................... ......................................................................... ......................................................................... (b) Calculate the K a value of propanoic acid using the pK a value in the Data Booklet. ......................................................................... ......................................................................... (c) + Use your answer from (b) to calculate the [H ] in an aqueous solution of propanoic acid of concentration 0.0500 mol dm −3 , and hence the pH of this solution. [2] [1] [3] ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... 223-163 –5– Option B – Medicines and drugs B1. (a) M03/420/S(3) Many drugs are taken orally. State three other ways in which drugs may be taken by a patient. .......................................................................... .......................................................................... .......................................................................... [2] (b) State what is meant by the term side effect. ......................................................................... ......................................................................... [1] (c) One common type of drug taken orally is the antacid. Antacids such as sodium hydrogencarbonate are taken to reduce stomach acidity. (i) State the names of two metals, other than sodium, whose compounds are often used in antacids. ..................................................................... (ii) Give an equation for the neutralization of hydrochloric acid in the stomach by sodium hydrogencarbonate. ..................................................................... (iii) Explain how heartburn is caused. ..................................................................... ..................................................................... (iv) Explain why dimethicone is added to some antacids. ..................................................................... ..................................................................... [1] [1] [1] [1] 223-163 Turn over –6– B2. (a) (i) M03/420/S(3) State what is meant by the term analgesic. Explain the difference in the mode of action of mild and strong analgesics. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... [3] (ii) State the general names of the two functional groups attached to the benzene ring in a molecule of aspirin. ..................................................................... [2] (iii) The use of aspirin can have beneficial effects for the user, but can also produce some unwanted side effects. State one beneficial effect (other than its analgesic action) and one unwanted side effect. ..................................................................... ..................................................................... ..................................................................... (b) Morphine is a naturally occurring analgesic that can be converted into codeine. (i) Calculate the difference in relative formula mass between morphine and codeine. ..................................................................... ..................................................................... (ii) Explain what is meant by developing tolerance towards codeine and state why this is dangerous. ..................................................................... ..................................................................... ..................................................................... ..................................................................... B3. The breathalyser can be used to detect ethanol in breath. Explain how this can be done, by reference to the substance used, the colour change and the type of reaction occurring. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 223-163 [2] [1] [2] [3] –7– Option C – Human biochemistry C1. Polypeptides and proteins are formed by the condensation reactions of amino acids. (a) Give the general structural formula of a 2-amino acid. M03/420/S(3) [1] (b) Give the structural formula of the dipeptide formed by the reaction of alanine and glycine. State the other substance formed during this reaction. [2] ......................................................................... (c) State two functions of proteins in the body. ......................................................................... ......................................................................... [2] (This question continues on the following page) 223-163 Turn over –8– (Question C1 continued) (d) M03/420/S(3) Electrophoresis can be used to identify the amino acids present in a given protein. The protein must first be hydrolyzed. (i) State the reagent and conditions needed to hydrolyze the protein, and identify the bond that is broken during hydrolysis. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... (ii) Explain how the amino acids could be identified using electrophoresis. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... [4] [4] 223-163 –9– C2. Fats and oils can be described as esters of glycerol, C3 H8O3 . (a) (i) Draw the structure of glycerol. M03/420/S(3) [1] (ii) Glycerol can react with three molecules of stearic acid, C17 H33COOH , to form a triglyceride. Deduce the number of carbon atoms in one molecule of this triglyceride. ..................................................................... [1] (iii) A triglyceride is also formed in the reaction between glycerol and three molecules of oleic acid, C17 H33COOH . State and explain which of the two triglycerides (the one formed from stearic acid or the one formed from oleic acid) has the higher melting point. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... (b) An oil sample containing 0.0100 mol of oil was found to react with 7.61 g of iodine, I 2 . Determine the number of C=C double bonds present in each molecule of the oil. ......................................................................... ......................................................................... ......................................................................... ......................................................................... [3] [2] 223-163 Turn over – 10 – Option D – Environmental chemistry M03/420/S(3) D1. The demand for drinking water continues to be a problem for the world. About 97 % of all the water on the planet is present in the seas and oceans and most of the rest is in ice caps or glaciers. (a) One method used to provide drinking water from sea water is reverse osmosis, which uses a partially permeable (semipermeable) membrane. (i) Outline the terms osmosis and partially permeable membrane. Osmosis: ..................................................................... ..................................................................... Partially permeable membrane: ..................................................................... ..................................................................... (ii) Explain the technique of reverse osmosis used to produce drinking water from sea water. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... (iii) Suggest one way in which a householder could reduce the amount of water used. ..................................................................... ..................................................................... [1] [3] [2] (This question continues on the following page) 223-163 – 11 – (Question D1 continued) (b) M03/420/S(3) Water that allows marine life to flourish needs a high concentration of dissolved oxygen. Several factors can alter the oxygen concentration. (i) State how an increase in temperature affects the oxygen concentration. ..................................................................... (ii) Eutrophication is a process that decreases the oxygen concentration of water. Explain how the accidental release of nitrates into a river can cause eutrophication. ..................................................................... ..................................................................... ..................................................................... ..................................................................... ..................................................................... [2] [1] (c) Much drinking water is treated before use with either chlorine or ozone. State two advantages and two disadvantages of using ozone instead of chlorine. Advantages: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................... .......................................................................... .......................................................................... Disadvantages: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......................................................................... .......................................................................... .......................................................................... [4] 223-163 Turn over – 12 – M03/420/S(3) D2. Waste water (sewage) from homes and industries varies greatly in its content, but it is desirable to treat it before it is returned to the environment, especially to reduce the Biological Oxygen Demand (BOD). (a) State what is meant by the term Biological Oxygen Demand. ......................................................................... ......................................................................... ......................................................................... ......................................................................... (b) Describe the main features of the activated sludge process used in secondary treatment, and state the main impurities removed during this treatment. ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... [5] [2] 223-163 – 13 – Option E – Chemical industries M03/420/S(3) E1. The oil industry converts most crude oil into fuels using several different processes, including fractional distillation, cracking and reforming. (a) Describe and explain how crude oil is converted into several fractions in a fractionating column. ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... ......................................................................... (b) All methods of cracking use high temperatures, but the other conditions vary, depending on the types of product required. (i) State the name of a catalyst used in catalytic cracking. Write an equation for the cracking of the straight-chain molecule C14 H30 into two products, assuming that only the central C–C bond breaks. ..................................................................... ..................................................................... ..................................................................... (ii) Hydrocracking is used to produce high-grade gasoline. Name the substance added to the feedstock and state one characteristic structural feature of the hydrocarbons produced. ..................................................................... ..................................................................... ..................................................................... (c) One type of reforming is called aromatization. Write an equation for this process, starting with hexane. State one use for the inorganic product formed. .......................................................................... .......................................................................... .......................................................................... [2] [2] [4] [2] 223-163 Turn over – 14 – M03/420/S(3) E2. Several monomers are produced by the oil industry and used in polymer manufacture. Examples include propene, styrene and vinyl chloride. (a) (i) Draw the structural formula of propene. [1] (ii) Isotactic polypropene has a regular structure, while atactic polypropene does not. Draw the structure of isotactic polypropene, showing a chain of at least six carbon atoms. State and explain how its properties differ from those of atactic polypropene. [3] ..................................................................... ..................................................................... ..................................................................... ........
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