EJC Prelim H1 Chemistry Paper 2 QP

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2025 General Certificate of Education Advanced Level Higher 1 CANDIDATE NAME CIVICS GROUP 2 4 – INDEX NUMBER CHEMISTRY Paper 2 Structured Questions 8873/02 02 September 2025 2 hours Candidates answer on the Question Paper Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Do not use paper clips, highlighters, glue or correction fluid. Write your name, civics group, registration number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Section A Answer all questions. Section B Answer one question. The number of marks is given in brackets [ ] at the end of each question or part question. A Data Booklet is provided. The use of an approved scientific calculator is expected, where appropriate. For Examiner’s Use Section A 1 / 15 2 / 10 3 / 16 4 / 10 5 / 9 Section B 6 / 7 / 20 Total / 80 This document consists of 25 printed pages and 3 blank pages.

2 © EJC 8873/02/J2Prelims/25 Section A Answer all questions in this section. 1 (a) Fig. 1.1 shows the trend for the third ionisation energies of a series of consecutive elements from the second and third period of the Periodic Table. Fig. 1.1 (i) Define the term third ionisation energy, with the aid of an equation for element A. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [2] (ii) Explain the general trend in the 3rd ionisation energy from element C to I. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [2] A B C D E F G H I 3rd ionisation energy element I

3 © EJC 8873/02/J2Prelims/25 [Turn over (iii) Explain the decrease in the 3rd ionisation energy from element D to E. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [1] (iv) Deduce which group element C is found in. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [2] (b) ⁵³X is an element produced by the decay of the radioactive isotope ⁵³Y. Complete Table 1.1. Table 1.1 species number of protons number of neutrons number of electrons electronic configuration 53 3 24 X + 1s2 ................................ .................. [2] (c) Catalytic converters are essential components in vehicle exhaust systems designed to reduce air pollution. It reduces harmful emissions from vehicle exhaust by using metals such as platinum, palladium, and rhodium as catalysts. (i) The metal catalysts in the catalytic converter are applied in the form of nanoparticles. Define the term nanoparticles. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [1]

4 © EJC 8873/02/J2Prelims/25 (ii) Suggest how the catalytic converter, using the metals in nanoparticle form, is expected to reduce the cost of the converter while maximising its efficiency. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [2] (iii) The harmful gases in the catalytic converters include carbon monoxide, nitrogen and unburnt hydrocarbons. State the type of catalysis and outline the mode of action as the metal catalysts convert the harmful gases into less harmful emissions. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ......................... [3] [Total: 15]

5 © EJC 8873/02/J2Prelims/25 [Turn over BLANK PAGE

6 © EJC 8873/02/J2Prelims/25 2 When baking bread, a mixture of ingredients including table salt (NaCl), sugar, water, butter and yeast are combined and then heated in an oven. During baking, both chemical and physical changes involving different types of bonding occur. (a) NaCl is added for flavour enhancement and to contribute to the structure, texture and overall quality of the bread. (i) State and define the type of bonding in solid NaCl. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ........................ [1] (ii) Compare the electrical conductivities of NaCl in the solid and molten states . Explain your answer. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ .......................