EJC Prelim H2 Chemistry Paper 3 QP

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2025 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 4 – INDEX NUMBER CHEMISTRY Paper 3 Free Response 9729/03 15 September 2025 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staplers, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. 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. 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 3 A1 / 20 A2 / 20 A3 / 20 B4 or 5 / 20 Total / 80 This document consists of 32 printed pages.

2 © EJC 9729/03/J2Prelim/25 Section A Answer all the questions in this section. 1 Indirect calorimetry is used to estimate energy expenditure in humans by measuring the difference in oxygen concentration between inhaled and exhaled air. During aerobic respiration at 37 ºC, glucose, C 6H12O6, is oxidised to carbon dioxide and water while producing energy as shown in reaction 1 below. reaction 1 C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l) HꝊ = –2818 kJ mol−1 (a) (i) It is assumed that there are negligible intermolecular forces of attraction between gas particles in an ideal gas. State two other basic assumptions of kinetic theory as applied to an ideal gas. [2] (ii) Air contains about 21% oxygen, by volume. Exhaled air contains 14% oxygen. At complete rest, a typical adult exchanges approximately 500 cm3 of air per breath at a rate of 12 times per minute at a temperature of 37 ºC at 1 atmospheric pressure. By assuming oxygen to be an ideal gas, calculate the volume of oxygen gas consumed per minute. Hence, determine amount of oxygen gas used per minute. [3] (iii) Assuming that the oxygen inhaled is used for respiration directly, u se relevant information in reaction 1 and your answer in (a)(ii), calculate the approximate amount of energy released per minute. [1] ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ...........................

3 © EJC 9729/03/J2Prelim/25 [Turn Over ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... ................................ ................................ ................................ ........................... (b) Glucose, C6H12O6, is the ubiquitous source of energy for cells in the body. (i) Define the standard enthalpy change of formation of glucose, C6H12O6(s). [1] (ii) Use the following data, reaction 1 and appropriate data from the Data Booklet, to construct an energy cycle and calculate the standard enthalpy change of atomisation of C(s). Show your working. enthalpy change of formation of C6H12O6(s) = –1270 kJ mol–1 enthalpy change of combustion of H2(g) = –286 kJ mol–1 [3] ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ .............................

4 © EJC 9729/03/J2Prelim/25 ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. (c) Glucose exists in two forms, -glucose and -glucose as shown in Fig. 1.1. If a solution of -glucose is left some time, it will come into dy