IJC H2 CHEM P2

INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 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 24 September 2009 1 hour 30 minutes 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. Answer all questions in the space provided. A Data Booklet is provided. For Examiner’s Use 1 11 2 11 3 12 4 11 5 15 Total 60 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 14 printed pages. Innova Junior College [Turn ove

PRELIM 2  INNOVA 9746/02/09 [Turn Over 2 For Examiner’s Use Answer ALL questions on the space provided. 1 2 identical gas syringes A and B, each with a volume of 200 cm 3 are filled with a volatile liquid which behaves as an ideal gas in vapour state. 1 g and 2 g of the liquid is placed in gas syringes A and B respectively and warmed. When the temperature reaches 60 °C, all the liquid evaporate in gas syringe A and the pressure is 80 kPa. (a) (i) Calculate the temperature in gas syringe A when the pressure is 120 kPa. (ii) Calculate the temperature when all the liquid evaporates in gas syringe B when the pressure is 120 kPa. (iii) Calculate the relative molecular mass of the gas. [4] (b) A student wrote the following in his notebook: “Potassium chloride has a very high boiling point while tetrachloromethane boils below 100 °C. This shows that ionic bond is stronger than covalent bond.” Do you agree with the above statement? ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ...................................................................................................................................[2]

3 For Examiner’s Use (c) A copper electrode was dipped in an aqueous solution containing 1 mol dm -3 CuSO4. When this half cell was connected via a salt bridge to the following half cell, a voltage was registered. 2CO2 + 2H+ + 2e H2C2O4 EӨ = – 0.49 V (i) Write the equation at the respective electrodes: Anode.................................................................................................................. Cathode............................................................................................................... (ii) Calculate the e.m.f of the cell. (iii) State and explain the effect of the E Ө cell of the reaction on adding aqueous potassium hydroxide to the CO2 / H2C2O4 half-cell. .............................................................................................................................. .............................................................................................................................. .............................................................................................................................. .............................................................................................................................. .............................................................................................................................. (iv) Explain why it is not possible to use E Ө value reliably to determine if a reaction will occur. .............................................................................................................................. .............................................................................................................................. [5] [Total: 11] Copper electrode 1 mol dm-3 CuSO4 (aq) CO2 gas at 25oC, 1 atm salt bridge 1 mol dm-3 of H2C2O4 (aq) / H+ (aq) platinum electrode V PRELIM 2  INNOVA 9746/02/09 [Turn Over

4 For Examiner’s Use 2 (a) When a mixture of silicon dioxide and carbon is heated in a stream of chlorine, silicon tetrachloride and carbon monoxide are formed. (i) Write an equation for the reaction described above in which silicon tetrachloride is formed. .............................................................................................................................. (ii) Melting point of silicon dioxide is 1883 K. Relate the melting point of the silicon dioxide to its structure and bonding. .............................................................................................................................. .............................................................................................................................. .............................................................................................................................. (iii) Silicon dioxide and silicon tetrachlori de each behaves differently when added to water. 1. Write an equation for the reaction that occurs when separate samples of silicon dioxide and silicon tetrachloride are added to an excess of water. Equation ....................................................................................................... 2. What is seen when litmus solution is added to each of the resulting solution? Silicon dioxide with water ……..…………………………………………..…… Silicon tetrachloride with water ………………………………………………… [4] (b) Hydrogen sulphide, H 2S smells of rotten eggs and is highly poisonous. 1 mole of hydrogen sulphide can react with 2 moles of boron trifluroide, BF 3, to form Compound C only. (i) Draw a diagram to illustrate the shape of and bonding in Compound C. (ii) Gaseous hydrogen sulphide is appreciably soluble in water to give a resulting solution that turns universal indicator yellow. Write an equation, with state symbols, to illustrate the solubility of hydrogen sulphide with water. …………………………………………………………………………………….…….. [2] PRELIM 2  INNOVA 9746/02/09 [Turn Over

5 For Examiner’s Use (c) (i) When aqueous ammonia was added to an aqueo