DHS_H2_CHEM_P1

2 BLANK P AGE [Turn Over

3 Section A For each question, there ar e four possible answers A, B, C, and D. Choos e the one you consider to be correct. 1 When 10.0 cm3 of a 0.10 mol dm–3 solution of alkali metal salt MXO3 was reduced with an excess of acidified potassium iodide solution, the resulting iodine required 60.0 cm 3 of 0.10 mol dm –3 sodium thiosulfate solution for its reduction. The anion could be reduced to A XO2 B XO2– C XO– D X– 2 10 cm3 of a hydrocarbon is mixed with 100 cm 3 of oxygen gas which is in excess. The mixture is exploded and after it is cooled to room temperature, the residual gase s occupy a volume of 80 cm 3. Upon passing the gases through potassium hydroxide, th is volume decreases to 50 cm3. What is the formula of the unknown hydrocarbon? A C3H6 B C3H8 C C4H8 D C4H10 [Turn Over

4 3 The use of Data Booklet is relevant to this question. The successive ionis ation energies, in kJ mol –1, of an element X are given below. 870 1800 3000 3600 5800 7000 13200 What is element X? A 33As B 53I C 8O D 52Te 4 A 10.0 dm 3 sample of oxygen at a pressure of 250 kPa and 3.0 dm 3 sample of nitrogen at a pressure of 500 kPa are introduced into a 2.5 dm 3 vessel at room temperature. What is the total pressure in the vessel? A 750 kPa B 1200 kPa C 1600 kPa D 1950 kPa 5 Given that the standard ent halpy change of combustion of but-1-ene and ethene are p and q kJ mol–1 respectively. What is the standard enthalpy change of the reaction: 2C2H4(g)  C4H8(g)? A 2q – p kJ mol–1 B (p + q)/2 kJ mol–1 C q – 2p kJ mol–1 D (q – p)/2 kJ mol–1 [Turn Over

5 6 The data below refers to the st andard molar enthalpy changes of combustion of some members of the alkanes. Alkane Hc /kJ mol–1 CH4 –890 C2H6 –1560 C3H8 –2220 C4H10 –2880 C5H12 –3510 C6H14 –4190 Another alkane X has a standard enthalpy c hange of combustion of –6780 kJ mol –1. The formula of X is likely to be A C9H20 B C10H22 C C11H24 D C12H26 7 The data below refers to the radii and charges of six ions. Ion P2+ Q + R + T 2– U – V – Radius/nm 0.16 0.19 0.15 0.16 0.19 0.15 PT, QU and RV are ionic solids of the same lattice structure. Which one of the following gives the correct order of their la ttice energies with the lowest numerical value first? A PT RV QU B PT QU RV C RV QU PT D QU RV PT