2024 Prelims NYJC H2 Chem P3 (Ans)

[Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS CHEMISTRY 9729/03 Paper 3 Free Response 12 September 2024 2 hours Candidates answer on the Question Paper Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and class 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. Do not use staples, 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. Circle the question you attempted in the box below. 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 1 /20 2 /20 3 /20 4 or 5 /20 Total /80 This document consists of 34 printed pages and 1 blank page. H

2 H2 Chemistry 9729/03 NYJC J2/24 PX [Turn Over For Examiner's Use Section A Answer all questions in this section. 1 Acrylic acid is a major building block used in the manufacture of a wide range of industrial and consumer products. In 2022, the global market for acrylic acid was approximately 6.7 million tonnes valued at USD 14.1 billion. O OH acrylic acid (a) One method of synthesising acrylic acid is by reacting propene and steam with palladium (Pd) catalyst in a fuel cell as shown in Fig. 1.1 . Pd serves as both an electrode and a catalyst in the fuel cell. Propene is pumped in at the Pd electrode, while air (as a source of oxygen) is pumped in at the other electrode (platinum, Pt). The cell is operated in the gas phase at 365 K and atmospheric pressure. Electricity is generated during the reaction, making th e process economically viable. Fig. 1.1 (i) Explain fully why Pd is suitable to serve both roles in the fuel cell. [2] Pd is able to serve as an electrode as it is a good electrical conductor due to presence of delocalised valence electrons which can act as charge carriers. [1] Pd is able to serve as a (heterogeneous) catalyst as it is a transition metal which contains partially filled (4)d subshell/orbitals which can accept electrons from the reactant molecule/ are able to form weak temporary bonds with reactant molecules during adsorption. [1] Cation exchange membrane (H3PO4 in silica w