contains four sections, SECTION A to SECTION D. Instructions: Answer all questions in SECTION A – SECTION D. Make sure that the section heading is included and your answers are correctly numbered. The assignment must have a completed cover sheet. It must be placed in the drop- box on or before the deadline. st SECTION A ELECTRONIC STRUCTURE & IONIZATION ENERGY 2. Write the electronic structure in s,p,d notation of the following: O, Na, Na+, A1, Cl- and co (Total 6 Marks) Write the electronic configuration in box notation of the following: N, Si and Ni (Total 3 Marks) 3.

A coffee-cup calorimeter contains 55. cm3 of a dilute solution of copper(ll) sulfate at a temperature of 22. 8 oc. A small amount of zinc powder also at 22. 8 oc is added to the solution. Copper metal is formed, and the temperature of the solution rises to 32. 3 oc. The copper is collected, dried and weighted, when it is found to have a mass of 0. 324 g. Calculate the total amount of energy released in this reaction, ignoring the heat capacity of the zinc and the calorimeter (Take the specific heat capacity of the solution as 4. J g-1 K-1). Calculate the enthalpy change for this reaction per mole of the copper formed. 15. Use the values for average bond enthalpies (E) from the table below to calculate the enthalpy changes in each of the reactions: (a) and (b) Bond c-c E/kJ mol-1 346 c=c 611 412 c=o 743 339 H-CI 431 497 CH4 (g) + 202(g) O C02(g) + 2H20(g) CH2 = CH2(g) + HCl(g) O CH3CH2Cl(g) How would your answer to (a) compare to the data book value for the (2 Marks) standard enthalpy of combustion of methane? Explain your answer. Total 8 Marks) 16. (a) Draw a diagram of the energy distribution of gas particles in a system at one temperature Tl . On the same diagram, show the shape the distribution at (3 Marks) ome higher temperature T2. Relate the two curves in (a) to the change in the rate of a gas phase reaction (2 with increased temperature. Draw a labelled energy profile showing the energy changes during an endothermic reaction. Use this and the diagram drawn in (a) to explain how (4 Marks) catalysts increase the rate of reactions. Total 9 Marks) Turn to page 5 for SECTION A – Question 17. 4 17. enthalpy of formation of ethane, OHf [C2H6]. 2c(s) + 3H2(g) -+ C2H6 (g) OHc carbon OHc hydrogen OHc ethane -394 kJ mol-l -286 kJ mol-l -1560 kJ mol-l Use the values for average bond enthalpies (E) from the table below along with the standard enthalpy of atomisation of carbon to calculate the standard enthalpy of formation of ethane, OHf [C2H6] using the equation given in (a). Structural formula of ethane: -1 346 E/kJ mol = 717 kJ mol-l 18.

Comment briefly on the discrepancy between the two calculated values for the standard enthalpy of formation of ethane in (a) and (b). Stating, with a reason, (3 which of the two values is likely to be more accurate. (Total 10 Marks) Given the following data, construct a Hess’s Law cycle and calculate the standard nthalpy of hydration of ethene C2H4(g) + H20(l) -+ C2H50H (l) ethene ethanol OHf ethene = +52 kJ mol-l OHf water OHf ethanol -278 kJ mol-l 19.

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The standard molar enthalpy of combustion of propanoic acid is -1527. 2 kJ mol-l . Given that the standard molar enthalpy change of formation of water is -285. 5 kJ mol-l and that of caron dioxide is -393. 5 kJ mol-l, construct a Hess’s Law cycle and calculate the standard molar enthalpy change of formation of propanoic acid. TOTAL FOR SECTION A 5 108 Marks Part A RATES OF REACTION Two gases react according to the equation: X (g) + 2Y(g) XY2(g) Experiments were done at 7000C to determine the rate equation.

The following results were obtained: Experiment Initial [X] Initial [Y] Initial rate of formation ofXY2 number [mol dm-3 [mol dm-3 [mol dm-3 s-l 0. 1 1 x 10-4 0. 2 4 x 10-4 State with reasons the order with respect to X State with reasons the order with respect to Y Write the rate equation for the reaction (1 Mark) Using the results from experiment 1 , calculate the value of the rate constant for (2 the reaction and state its units. Hydrogen and nitrogen oxide react according to the equation: 2H2 (g)

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