AJC_H2_CHEM_P2

AJC JC2 PRELIM 2014 9647/02/H2 [Turn over ANDERSON JUNIOR COLLEGE 2014 JC2 PRELIMINARY EXAMINATIONS     NAME:______________________________ PDG:_____ /13 Register No: _____   CHEMISTRY 9647/02 Higher 2 3 September 2014 Paper 2 Structured Questions 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, PDG and register number on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all the questions. The use of an approved scientific calculator is expected where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Paper 2 1 Total / 72 2 3 4 5 This document consists of 24 printed pages and 1 blank page.

2 AJC JC2 PRELIM 2014 9647/02/H2 [Turn over  1 Planning (P) At any temperature, equilibrium can be established between a liquid X and the vapour given off by that liquid. The pressure exerted by the vapour in equilibrium with the liquid is known as the vapour pressure. X(l) X(g) As the temperature of the system is raised, the vapour pressure increases. When this vapour pressure becomes equal to the surrounding (ambient) air pressure, the liquid boils. When the liquid contains a dissolved solid (solute), the vapour pressure above the liquid is reduced. To investigate how the boiling point of an aqueous solution of potassium chloride changes with concentration, a series of known, but different, concentrations of potassium chloride is prepared. Each solution is heated and its boiling point is determined. A graph of boiling point against concentration is then plotted. (a) (i) By considering how the vapour pressure changes as the concentration of aqueous potassium chloride increases, predict and explain how the boiling point of the solution will be affected by the concentration of the solution. …………………………………………………………… ………………………………………....... …………………………………………………………… ………………………………………....... …………………………………………………………… ………………………………………....... (ii) Display your prediction in the form of a sketch graph, labelling clearly the point representing the boiling point of pure water and its value, stating the units. [3] boiling point 0 concentration of potassium chloride

3 AJC JC2 PRELIM 2014 9647/02/H2 [Turn over  (b) Draw a diagram of the assembled apparatus you would use in the experiment. You should use only the apparatus normally found in a school or college laboratory and show clearly (i) how the solution will be heated an