9701_s06_qp_4
A paper of Chemistry, 9701
Questions:
5
Year:
2006
Paper:
4
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0
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1
The oxidation of nitrogen monoxide occurs readily according to the following equation. NO+  O2⎯→ NO2The following table shows how the initial rate of this reaction depends on the concentrations of the two reactants. Use the data to determine the order of reaction with respect to each of the reagents. order with respect to NO ………………………… order with respect to O2 ………………………… Write the rate equation for the reaction, and use it to calculate a value for the rate constant, k, stating its units. rate equation numerical value of k = ………………………… units of k ………………………… Use your rate equation in to calculate the rate of reaction when [NO] = [O2] = 0.0025 mol dm–3. rate of reaction =………………………… [NO] / mol dm–3 0.0050 0.0050 0.010 [O2] / mol dm–3 0.0050 0.0075 0.0075 initial rate / mol dm–3s–1 0.02 0.03 0.12 [T Nitrogen monoxide plays an important catalytic role in the oxidation of atmospheric SO2 in the formation of acid rain. State the type of catalysis shown in this process. Explain the steps involved in this process by writing equations for the reactions that occur. Examiner s Use
12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur
8. Reaction kinetics  →  8.1. Rate of reaction
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2
Monuments made of marble or limestone, such as the Taj Mahal in India and the Mayan temples in Mexico, are suffering erosion by acid rain. The carbonate stone is converted by the acid rain into the relatively more soluble sulphate. CaCO3+ H2SO4→CaSO4+ H2O+ CO2acid rain Write an expression for the solubility product, Ksp, of CaSO4, stating its units. The Ksp of CaSO4 has a numerical value of 3 x 10–5. Use your expression in to calculate [CaSO4] in a saturated solution. Hence calculate the maximum loss in mass of a small statue if 100 dm3 of acid rain falls on it. Assume the statue is made of pure calcium carbonate, and that the acid rain becomes saturated with CaSO4. The life of such monuments is now being extended by treating them with a mixture of urea and barium hydroxide solutions. After soaking into the pores of the carbonate rock, the urea gradually decomposes to ammonia and carbon dioxide. The carbon dioxide then reacts with the barium hydroxide to form barium carbonate. (NH2)2CO+ H2O⎯→ 2NH3+ CO2Ba(OH)2+ CO2⎯→ BaCO3+ H2OAcid rain then converts the barium carbonate to its sulphate. BaCO3+ H2SO4⎯→ BaSO4+ H2O+ CO2Barium sulphate is much less soluble than calcium sulphate. A saturated solution contains [Ba2+] = 9.0 x 10–6mol dm–3. Explain why barium sulphate is less soluble than calcium sulphate. Use [T Write an expression for the Ksp of barium sulphate and use the data to calculate its value. Explain what is meant by the term lattice energy. Predict, with a reason, how the lattice energy of BaSO4 might compare with that of MgSO4. Examiner s Use
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur
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A transition element X has the electronic configuration [Ar] 4s2 3d3. Predict its likely oxidation states. State the electronic configuration of the ion X3+. Potassium manganate(, KMnO4, is a useful oxidising agent in titrimetric analysis. Describe how you could use a 0.0200 mol dm–3 solution of KMnO4 to determine accurately the [Fe2+] in a solution. Include in your description how you would recognise the end-point in the titration, and write an equation for the titration reaction. A 2.00 g sample of iron ore was dissolved in dilute H2SO4 and all the iron in the salts produced was reduced to Fe2+. The solution was made up to a total volume of 100 cm3. A 25.0 cm3 portion of the solution required 14.0 cm3 of 0.0200 mol dm–3 KMnO4 to reach the end-point. Calculate the percentage of iron in the ore. Use [T High-strength low-alloy (HSLA) steels are used to fabricate TV masts and long span bridges. They contain very low amounts of phosphorus and sulphur, but about 1% copper, to improve resistance to atmospheric corrosion. When dissolved in nitric acid, a sample of this steel gives a pale blue solution. What species is responsible for the pale blue colour? Describe and explain what you would see when dilute aqueous ammonia is added to this solution. Examiner s Use
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
12. Nitrogen and sulfur  →  12.1. Nitrogen and sulfur
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The amino acids tyrosine, lysine and glycine are constituents of many proteins. State the reagents and conditions you could use to break proteins down into amino acids. Draw a ring around each chiral centre in the above molecules. In aqueous solution amino acids exist as zwitterions. Draw the zwitterionic structure of glycine. For each of the following reactions, draw the structure of the organic compound formed. glycine + excess NaOHtyrosine + excess NaOHUse CH2 C O CH OH tyrosine H2N OH (CH2)4 NH2 C O CH lysine H2N OH H C O CH glycine H2N OH [T lysine + excess HCltyrosine + excess Br2 Draw the structural formula of a tripeptide formed from all three of these amino acids, showing clearly the peptide bonds. The formula of part of the chain of a synthetic polyamide is shown below. Identify the repeat unit of the polymer by drawing square brackets around it on the above formula. Draw the structures of the two monomers from which the polymer could be made. Examiner s Use CH2 CH2 CH2 NH NH NH CO CO CO CH2 CH2 NH NH CO
20. Polymerisation  →  20.1. Addition polymerisation
14. Hydrocarbons  →  14.2. Alkenes
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Benzocaine is an important local anaesthetic used in skin creams for sprains and other muscular pains. It can be made by the following route. Suggest reagents and conditions for each of the above four reactions. I II III IV Draw steps to show the mechanism of reaction I. Another local anaesthetic is amylocaine, which can be made from compound X. Apart from the benzene ring, name two functional groups in the molecule of compound X. Use CH3 I CH3 NO2 II CO2H NO2 III CO2H NH2 IV CO2CH2CH3 NH2 benzocaine amylocaine X CH2 CH3 CH2CH3 NH2 C C O O CH2 CH3 CH3 CH3 CH2CH3 N C C O O Explain whether compound X would be more or less basic than benzocaine. Examiner s Use
21. Organic synthesis  →  21.1. Organic synthesis
13. An introduction to AS Level organic chemistry  →  13.1. Formulas, functional groups and the naming of organic compounds
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