SAJC H2 CHEM P1

[Turn over 2 Section A For each question, there are four possible answers: A, B, C and D. Choose the one you consider correct and record your choice. The oxide of a metal, MO, reacts with sulfuric acid to form its corresponding sulfate, MSO4, and water. When 5 g of pure MO is reacted with 100 cm3 of 1 mol dm-3 of sulfuric acid, the excess acid required 21.45 cm3 of 1 mol dm-3 NaOH for complete neutralisation. Determine the Ar of the metal, M. A 40.0 B 47.5 C 56.0 1. D 63.5 70 cm3 of a mixture of methane and ethene were exploded in 200 cm3 of oxygen. The volume of the residual gases was found to be 130 cm3. On being shaken with sodium hydroxide, the final volume was found to be 35 cm3. What is the composition of the mixture? (All volumes are measured at r.t.p) Volume of methane / cm3 Volume of ethene / cm3 A 20 50 B 35 35 2. C 45 25 D 50 20

[Turn over 3 Which of the following species in their ground states have four unpaired electrons? A Si B S C Fe 2+ 3. D Cr3+ Element X has a valence electronic configuration of 2s 2 2p1 while element Y has a valence electronic configuration of 2s2 2p4. What is the formula of the compound formed between X and Y? A XY B X 2Y3 C X 3Y2 4. D X 3Y6 Which of the following compounds has the highest boiling point? A NO 2 B SO2 C SiO2 5. D H2O

[Turn over 4 The diagram below shows part of the structure of ordinary ice. O H H H O H O H H H O H H O H H O Which of the following statements is not true? A The bond angle in ice is 104.5o. B The density of water is higher than that of ice. C Ice has a cage-like “open” structure. 6. D Both ice and water have covalent bonding as well as hydrogen bonding. A small spacecraft of capacity 20 m3 is connected to another of capacity 50 m3. Before connection, the pressure inside the smaller craft is 40 atm and that inside the larger is 150 atm. If all measurements are made at the same temperature, what is the pressure in the combined arrangement after connection? A 190 atm B 119 atm C 95 atm 7. D 78 atm

[Turn over 5 Which of the following diagrams correctly shows the graph of V against T for a fixed mass of ideal gas at constant pressure? A T / oC V B T / oC V C T / oC V 8. D T / oC V

[Turn over 6 In an experiment to determine the enthalpy change of neutralisation of nitric acid, 25 cm3 of solution containing 0.04 mol of HNO3 is placed in a plastic cup of negligible heat capacity. A 25 cm3 sample of aqueous sodium hydroxide containing 0.04 mol of NaOH, at the same initial temperature, is added and the temperature rises by 20 C. If the heat capacity per unit volume of the final solution is 4.2 J K-1 cm-3, what is the numerical value of the enthalpy change of neutralisation of nitric acid? A  0.04 273 20 4.2 50   B 0.08 20 4.2 50   C 0.04 20 4.2 50  9. D 0.08 20 4.2 25  The use of the Data Booklet is relevant to this question. Hydrogen peroxide is commonly used as a bleaching agent in hair dyes and has the following structural formula. H O O H What is the enthalpy change of atomisation of 1 mole of gaseous hydrogen peroxide? A 610 kJ mol-1 B 956 kJ mol-1 C 1070 kJ mol-1 10. D 1416 kJ mol-1 A titration is carried out between 10.0 cm3 of 0.05 mol dm-3 manganate(VII), MnO4 -, solution and 0.05 mol dm-3 of acidified methanoate, HCO2 - solution. The products formed are MnO4 2- and CO3 2-. What is the volume (in cm3) of HCO2 - required for complete reaction? A 5.00 B 10.50 C 20.00 11. D 25.00

[Turn over 7 The use of the Data Booklet is relevant to this question. Which of the following species can cause the oxidation of nickel, Ni? A Cr3+ B Pb2+ C Cu 12. D Cl- Two gases, P and Q, react as follows. P(g) + Q(g) 3R(g) A mixture containing P and Q is heated in a 2 dm3 closed vessel and the reaction is allowed to reach equilibrium. The following graph shows how the number of moles of each gas varies with time. P and Q 0.50 0.40 0.35 0.45 0 moles time R What is the value of the equilibrium constant Kc for this reaction? A 0.372 B 0.744 C 0.778 13. D 1.286

[Turn over 8 Which of the following options is correct for the following equilibrium? 3H2 (g) + N2 (g) 2NH3 (g) Condition Position of equilibrium Kp Rate of forward reaction A Increase in temperature Right Increase Increase B Addition of catalyst No change No change No change 14. C Decrease in pressure Left No change Decrease D Addition of H2 (g) Right Increase Increase H =- 92 kJ mol-1 Given that the Ksp for silver hydroxide, AgOH, is 1.52 x 10-8 mol2 dm-6 at 298 K, calculate the pH of the solution at equilibrium. A 2.6 B 3.9 C 10.1 15. D 11.4 Calculate the pH of a buffer solution made by dissolving 8.2 g of sodium ethanoate (CH3COONa) in 500 cm3 of 0.100 mol dm-3 ethanoic acid. (Kb for ethanoate ion = 5.71 x 10-10 mol dm-3) A 4.06 B 5.06 C 9.24 16. D 9.54

[Turn over 9 Radioactive decay is a first order reaction. Carbon-14 is a radioactive element with a half-life of 5600 years. A piece of wood, containing carbon-14, from an ancient ship gives a count of 10 counts per minute, while carbon-14 obtained from new wood gives 15 counts per minute. What is the age of the ship? A 2800 years B 3276 years C 3733 years 17. D 8876 years The table below gives data for the reaction between Q and R at constant temperature. Experiment [Q] / mol dm -3 [R] / mol dm -3 initial rate / mol dm -3 s-1 1 0.3 0.2 4.0 × 10-4 2 0.6 0.4 1.6 × 10-3 3 0.6 0.8 6.4 × 10-3 What is the units of the rate constant for the reaction? A mol2 dm-6 s-1 B mol-2 dm6 s-1 C mol dm-3 s-1 18. D mol-1 dm3 s-1 Which of the following trend across Period 3 (Na to Cl) is always true? A The electrical conductivity of the element decreases. B The bonding in the oxides changes from ionic to covalent. C The melting point of the oxides decreases. 19. D The electronegativity of the elements decreases. The following elements are reacted with oxygen and the products are dissolved in water. The element which produces the solution with the greatest pH is A Na B Al C S 20. D P

[Turn over 10 How do the values of lattice energy and enthalpy change of hydration vary for Group II carbonates from magnesium to barium? Lattice energy Enthalpy change of hydration A less exothermic less exothermic B less exothermic more exothermic 21. C more exothermic less exothermic D more exothermic more exothermic Which of the following features of transition metals or their compounds make them suitable as heterogeneous catalysts for chemical reactions? A They have variable oxidation states. B They form stable complexes. C They have available 3d and 4s orbitals. 22. D They can undergo ligand exchange reactions. Which of the following pairs of compounds can be attacked by cyanide ions via nucleophilic reactions? A CH3CH2Cl and CH3COCH2CH3 B CH3CH2Cl and CH3COOCH3 C C6H5Cl and CH3COCH2CH3 23. D C6H5Cl and CH3COOCH3 Acarol is the active ingredient in many insecticides. Br C HO C O OC ( C H3)3 Br Acarol Which of the following statements about Acarol is true? A Acarol exhibits stereoisomerism. B Acarol forms white fumes with thionyl chloride. C Acarol changes hot, acidified K2Cr2O7 from orange to green. 24. D Acarol forms an orange precipitate with 2,4 dinitrophenylhydrazine.

[Turn over 11 Cannabis is a psychoactive drug which accumulates in the fatty tissues of the body. Compound W can be prepared from cannabis as shown in the following reaction sequence. CH3 HO (CH2)4CH3 OH CC H 3 H2C Cannabis CH3 -O (CH2)4CH3 CC H 3 H2C O-Step I CH3 HOOC(CH2)2O( CH2)4CH3 CC H 3 H2C