Set 2 Chemistry [Paper] 2

SECTION A Attempt only three questions in this section. 1.a) Define the following terms: (@01 mark) i. Bond energy. ii. Enthalpy of reaction. iii. Enthalpy of neutralization . 1.b) Use the following thermo chemical data to calcu late the enthalpy of the equation. (03 marks) 2C2H6(g) + 7O2(g) 6H2O(l) + 4CO2(g)  Enthalpy of formation of carbon dioxide = -394KJ/mol  Enthalpy of formation of water = -286KJ/mol  Enthalpy of formation of ethane = +85KJ/mol 1.c) Explain each of the following observations: (@03 marks) i. The enthalpy of neutra lisation of a weak acid with a strong base is less than that between a st rong acid with a strong base. ii. The bond energies of the halogens are in the order of: Cl-Cl Br-Br F-F I-I 1.d) During the experiment to determine the enthalpy of neutralisation between hydrochloric acid and sodium hydroxide solution is 25.0cm3 of 1.0M hydrochloric acid was pipetted in to a plastic beaker and titrated with 1.0M sodium hydroxide solution from the burette. The temperature of the solution was recorded every after addition of the sodium hydroxide solution in the table below. Vol.of NaOH adde (cm3) Temperature of soluton ( C) Temperature change ( C)0 10 20 25 30 35 40 45 22 24.7 27.4 28.2 28.5 28.3 28.0 27.8 0 2.7 5.4 6.2 6.5 6.3 6.0 5.8 i. Plot a graph of volume of sodium hydroxide solution added against temperature change. (03 marks) ii. Determine the maximum temperature change from the graph. (02 marks ) iii. Determine the volume of the sodium hydroxide solution at the end point. (01 mark) iv. Calculate the enthalpy of neutralisation of the reaction if 4.18KJ/mol/C/kg is the sp ecific heat capacity. (03 marks) 2. Zinc is a d -block element. 2.a) (i).Write the electronic configuration of Zinc. (01 …