DHS H2 CHEM P2

2 BLANK P AGE [Turn Over

3 1(a) The chlorides of sodium to phosphorus (NaC l, MgC l2, AlCl3, SiCl 4 and PCl 5) are separately added to water. (i) Sketch a graph to show the pH of the resulting solution, indicating clearly the pH of sodium chloride. [2] (ii) Account for the pH value of aluminium chloride. [1] (iii) Write equations for the reactions of silicon chloride and phosphorus pentachloride with water. [2] pH Na Mg Al Si P [Turn Over

4 (b) Under suitable conditions iodine and ch lorine react to give int erhalogen compound, IClx. When a pure sample of IClx was dissolved in an excess of aqueous potassium iodide, the iodine liberated requires 17.1 cm3 of 0.1 mol dm–3 of Na2S2O3 for the titration. On the other hand, the chloride ion liberated requires 12.8 cm3 of 0.1 mol dm–3 silver nitrate for complete precipitation. (i) Determine the value of x. Hence, write a balanced equation for the reaction between IClx and I–. [4] (ii) Sketch on the same axes, the variation of pV m / RT against p at 300K, for 1 mol of (I) an ideal gas and (II) IClx gas. Label your graphs clearly where V m is the gas molar volume. [2] pVm / RT p [Turn Over

5 (iii) Using the same axes as in (b)(ii), show the change at 700K for one mol of IClx. Explain your sketch. [2] [Total: 13] 2 This question is about a Group II element, barium and the reactions of its compounds. (a) Write a balanced chemical equation, with state symbols, for the decomposition of barium nitrate. [1] (b) How would you expect the decomposition temperature of barium nitrate to differ from that of calcium nitrate? Explain your answer. [3] [Turn Over

6 (c) Draw the dot-and-cross diagram of the NO3 – anion. [2] (d) The solid product formed in (a) reacts with dilute hydrochloric acid to give BaCl2 and H2O. Write a balanced chemical equation, with state symbols, for the reaction of BaCl2 with concentrated sulfuric acid. [1] (e) Predict the products formed from the reaction of barium bromide, BaBr2 with concentrated sulfuric acid. [2] (f) Suggest an explanation for the difference in products formed in (d) and (e). Support your explanation with relevant data from the Data Booklet. [3] [Total: 12] [Turn Over

7 3 The technology behind Direct M ethanol Fuel Cells (DMFC) is still in the early stages of development, but it has successfully powered mobile phones and laptop computers, the target end uses in futu re years. The fuel and oxygen are pumped continuously to the two electrodes which are made of platinum. (a) Write equations for the reactions which take place for the fuel cell. Anode: Cathode: Overall: [3] (b) Write the cell diagram. [1] (c) Give an advantage of the fuel cell with methanol as a fuel. [1] [Total: 5] (–) (+) Carbon dioxide Acidic electrolyte solution Cathode (CH3OH) Anode Methanol Water Air [Turn Over

8 4 Magnesium hydroxide, Mg(OH) 2, is sparingly soluble in water. The solubility product of magnesium hydroxide in water is 5.61 x 10–12 mol3 dm–9. (a) Write an expression for the solubility product, Ksp of magnesium hydroxide. [1] (b) Calculate the solubility of magnesium hydroxide in g dm –3 for a saturated solution of magnesium hydroxide at 25°C. [2] (c) Calculate the solubility of Mg(OH) 2 in 5.00 x 10–2 mol dm–3 aqueous sodium hydroxide. [2] (d) Equal volumes of solutions containing 5.0 x 10 –3 mol dm –3 magnesium nitrate and 6.0 x 10 –3 mol dm –3 of sodium hydroxide are mixed. Predict if a precipitate will be formed. Explain your answer with the aid of relevant calculations. [3] [Total: 8] [Turn Over

9 5 Complete the reaction scheme below by writi ng the structural formu la of the organic products (A-D) and the reagents and conditions (1-6) in the spaces below. O COOH C A 3 B 4 5 C H3 CN C H3 1 O O NH CH 3 6 2 D [Total: 10] [Turn Over

10 6 Oseltamivir is an antiviral drug that slows the sp read of non-resistant strains of the influenz a virus between cells in the body. It blocks the action of a viral enzyme called neuraminidase and has since been indicated for the treatment of H5N1 and H1N1 infection. The standard adult dosage is 75 mg twice daily. The relative molecula r mass of this drug is 312.4. ON H2 OOC H 3 C1 CH3 CH3 ON H CH3 oseltamivir 1 2 (a) A male adult patient has been put on a 5-day Tamiflu treatment. Calculate the total number of moles of Tamiflu tak en by this patient over this period o f treatment. [1] (b) Name the functional groups present in oseltamivir. [3] [Turn Over

11 (c) Neuraminidase is described as a tertiary protein. Explain what is meant by the term tertiary protein. [2] (d) Describe the hybridisation, geometry and bond angle about C 1 atom. [3] (e) Compare the basicity of N 1 and N 2 atom of oseltamivir. Explain which nitrogen atom has a lower pKb value. [3] [Total: 12] [Turn Over