Broadrick Prelim Ans

1 [Turn over Paper 1 1 2 3 4 5 6 7 8 9 10 C D D D B C D B C A 11 12 13 14 15 16 17 18 19 20 A C B A B C C B B C 21 22 23 24 25 26 27 28 29 30 C C B A A B D B D B 31 32 33 34 35 36 37 38 39 40 D C D A D C A A B B Section A 1 ai D 1 aii A 1 aiii E 1 aiv D 1 b C and F 1 5 2 ai The number of protons does not equal the number of electrons in T. 1 aii P and Q 1 b Relative atomic mass = 0.02 x 80 + 0.12 x 82 +0.12 x 83 +0.57 x 84 + 0.17 x 85 = 83.73 = 83.7 ( 3sf) 1 3 3 a Diamond and calcium oxide 1 b The molecules slide freely and randomly around one another. The molecules are closely packed and disorderly arranged. 1 1 c Calcium ion has higher charge of 2+ as compared with sodium ion of 1+. The electrostatic forces of attraction between calcium and oxide ions are stronger than that between sodium and oxide ions. Hence more heat energy is required to overcome the attractive forces. 1 1

2 [Turn over d Diamond has a three-dimensional tetrahedral structure where each carbon atom is covalently bonded to four neighbouring carbon atoms. There are no free electrons available to carry charge and conduct electricity. Hence it is a poor electrical conductor. 1 1 7 4 a M: iron(II) carbonate N: carbon dioxide O: iron(II) chloride P: iron(II) hydroxide 4 b FeCO 3(s) + 2H+(aq)  Fe2+(aq) + H2O(l) + CO2(g) [1] correct formule [1] correct coefficients and state cymbols 2 6 5 a No. of moles of dilute nitric acid = 24.00/1000 x 0.75 = 0.018 mol 1 b No. of moles of potassium oxide = 23.5 / 94 = 0.25 mol 0.25 mol of potassium oxide requires 0.50 mol of nitric acid to react completely. [Statement is needed to obtain the mark] Or 0.018 mol of HNO3 will require 0.009 mol of K2O to react completely dilute nitric acid is the limiting reactant. -allow ecf from (a) [no final mark if working does not convince nitric acid is limiting reactant] 1 1 1 c By mole ratio, 2 moles of dilute nitric acid produces 1 mole of water vapour. Number of moles of water vapour = 0.018/2 = 0.009 mol Volume = 0.009 x 24000 = 216 cm3 -allow ecf from (b) 1 1 6

3 [Turn over 6 a halogen melting point / oC boiling point / oC bromine -7 59 chlorine -103 -34 iodine 113 185 1 b Fluorine is more reactive than bromine. Fluorine displaces bromine from potassium bromide solution to form bromine, (which is reddish-brown). 1 1 c Yes. Iodine has the largest atomic radius / outer electrons are furthest from nucleus. Iodine’s outer electrons are most easily lost / least strongly attracted to nucleus / highest tendency to lose electrons / lowests effective nuclear charge. 1 1 5 7 a Energy changes: 1. The magnitude / size / value / amount of energy change is larger when calcium chloride is dissolved in wa