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