2022 ZSS Chem Prelims P2

Candidate Name: ___________________________ Index No: ____ Class: _______ Paper 2 6092 / 02 25 August 2022 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary Sch ool Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School Zhenghua Secondary School READ THESE INSTRUCTIONS FIRST Write your index number, class and name 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. Section A Answer all questions in the spaces provided. Section B Answer all three questions, the last question is in the form either/or. Answer all questions in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. A copy of the Periodic Table is printed on page 23. The use of an approved scientific calculator is expected, where appropriate. Name of Setter: Ms Natalie Tan Li Er This document consists of 23 printed pages including this Cover Page and the Periodic Table. [Turn over For Examiner’s Use Total ZHENGHUA SECONDARY SCHOOL PRELIMINARY EXAMINATION 2022 SECONDARY FOUR EXPRESS CHEMISTRY

2 Section A Answer all questions in this section in the spaces provided. The total mark for this section is 50. A1 Choose from the following list of substances to answer the questions below. nitrogen sodium oxide carbon dioxide silicon dioxide iron(II) chloride silver chloride zinc oxide diamond Each substance can be used once, more than once or not at all. (a) Which element has a giant covalent structure? …………………………………………………………………………………………...[1] (b) Which substance will react with potassium hydroxide to form precipitate which will change colour on standing? …………………………………………………………………………………………...[1] (c) Which compound exists as discrete molecules? …………………………………………………………………………………………...[1] (d) Which substance will dissolve to form an acidic solution? …………………………………………………………………………………………...[1] (e) Which substance can be added in excess to hydrochloric acid to form a soluble salt? …………………………………………………………………………………………...[1] [Total: 5]

3 A2 Silver dichromate, Ag2Cr2O7, is a red insoluble salt.