2023 MGS 6092 Prelim Chem P1, P2, MS

Page 2 of 17 Methodist Girls’ School Chemistry Sec 4 Preliminary Examination 2023 1 Ethylamine gas, C2H5NH2, and hydrogen chloride gas, HCl, react together to form a white solid, ethylamine hydrochloride. At which position in the tube would a ring of solid white ethylamine hydrochloride form? 2 Bromate ion, bromide ion and hydrogen ions react according to the equation shown. BrO3-(aq) + 5Br -(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(l) Some apparatus for measuring the change in the rate of this reaction is suggested. 1 gas syringe 2 balance 3 pH meter Which apparatus is suitable to measure the rate of this reaction? A 1 only B 3 only C 1 and 2 D 2 and 3 3 Some substances may be separated using paper chromatography. The diagram shows the results of running two mixtures in a suitable solvent. Which spot has an R f value of 0.4? start line

Page 3 of 17 Methodist Girls’ School Chemistry Sec 4 Preliminary Examination 2023 4 The diagram shows the structural formula of methylamine. What is the total number of electrons involved and not involved in the bonding of methylamine molecule? Total number of electrons involved in bonding Total number of electrons not involved in bonding A 6 4 B 6 6 C 12 4 D 12 6 5 Both calcium chloride and potassium chloride are ionic compounds. Which statement about these compounds is correct? A Potassium chloride has a higher melting point than calcium chloride because the potassium ion has a greater charge than calcium ion. B Calcium chloride and potassium chloride conduct electricity because positive and negative ions flow through the solid material. C Molten calcium chloride has a greater electrical conductivity than molten potassium chloride because calcium contributes more electrons to the delocalised ‘sea of electrons’ than potassium. D In the calcium chloride lattice, the ratio of calcium ions to chloride ions is half that of the ratio of potassium ions to chloride ions in the potassium chloride lattice. 6 Which sample contains the same number of the named particles as the number of molecules in 35.5 g of chlorine? A atoms in 16 g of sulfur B atoms in 23 g of sodium C molecules in 32 g of methane D molecules in 88 g of carbon dioxide

Page 4 of 17 Methodist Girls’ School Chemistry Sec 4 Preliminary Examination 2023 7 Sodium carbonate reacts with dilute hydrochloric acid. Na2CO3 + 2HCl → 2NaCl + H2O + CO2 A sample containing 0.0800 mol of sodium carbonate is added to a solution containing 0.100 mol of hydrochloric acid. What volume of carbon dioxide is produced at room temperature and pressure? A 0.96 dm3 B 1.20 dm3 C 1.92 dm3 D 2.40 dm3 8 Which statement about acids and bases is correct? A A 0.1 mol/dm 3 solution of ethanoic acid has a higher pH than a 0.1 mol/dm 3 solution of hy