2019 TMJC H2 Chem Prelim P3 QP

Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry __________________________________________________________________________________ H2 CHEMISTRY 9729/03 Paper 3 Free Response 23 September 2019 2 hours Candidates answer on Answer Booklet. Additional Materials: Answer Booklet Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and civics group on all your work you hand in. Write in dark blue or black pen on both pages in the answer booklet. You may use an HB pencil for any diagrams, graphs or rough working. Do not use paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer one question. A Data Booklet is provided. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. __________________________________________________________________________________ This document consists of 14 printed pages. TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry Section A Answer all the questions from this section. 1 Hydrocarbons, CxHy, are used extensively as sources of fuel in our modern day civilisation. (a) 10 cm3 of a gaseous hydrocarbon C5Hy was allowed to burn in an excess of oxygen at 300 ºC and 1 atm. In the reaction, there was an expansion of volume by 20 cm3. (i) Write a balanced equation, with state symbols, for the reaction at 300 ºC and 1 atm. [2] (ii) Determine the value of y. [2] Methane, CH4, is sometimes used in the production of hydrogen via a process known as steam reforming. CH4(g) + H2O(g) CO(g) + 3H2(g) (b) The steam reforming process is an endothermic reaction. (i) Using data from the Data Booklet , calculate a value for the enthalpy change of the forward reaction. [2] (ii) The actual value of the enthalpy change of reaction is found to be +206 kJ mol–1. Suggest a reason why your calculated answer in (i) differs from this value. [1] (c) At 600 K, t he value of the equilibrium constant, Kp, for the steam reforming reaction is 7.20 x 10–4. (i) Write the Kp expression for this reaction, giving its units. [2] (ii) Gaseous CH4, H2O and CO are introduced into a closed container at 600 K and their initial partial pressures are 1.20 atm, 2.10 atm and 1.80 atm respectively. Determine the partial pressure of H2 when equilibrium is reached. (You may assume that the extent of the forward reaction is small.) [3] (iii) Using information from (b), suggest how the temperature of the reaction can be changed so as to increase the yield of H2. Explain your answer. [2]

3 Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry (d) Additional hydrogen can be recovered using the carbon monoxide pro