SJI 2023 Y4 Prelim Chemistry Paper 2

ST JOSEPH’S INSTITUTION PRELIMINARY EXAMINATION 2023 (YEAR 4) CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY Paper 2 Candidates answer on the Question Paper. No Additional Materials are required. 6092/02 18 August 2023 1 hour 45 minutes (10:45 – 12:30) READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black fluid ink pen. You may use a soft pencil for any diagrams, graphs or rough working. 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. The use of an approved scientific calculator is expected, where appropriate. A copy of the Periodic Table is printed on page 2. For Examiner’s Use Section A / 50 Section B / 30 Total / 80 This document consists of 28 printed pages including this cover page.

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3 Section A (50 marks) Answer all questions in this section in the spaces provided. A1 The names of some aqueous salts are shown below. aluminium sulfate ammonium chloride calcium chloride magnesium sulfate silver nitrate sodium iodide zinc nitrate Use the names of the salts to answer the following questions. You may use each salt once, more than once or not at all. (a) Which salt(s) undergo a redox reaction when reacted with bromine gas? ……………….…………………………………………………………………… ……..[1] (b) Which two salts react with each other to form a yellow precipitate? ……………….…………………………………………………………………………..[ 1] (c) Which salt(s) form a precipitate which is soluble in excess aqueous sodium hydroxide? ……………….…………………………………………………………………………..[1] (d) Which salt(s) form an alkaline gas when heated with excess aqueous sodium hydroxide and aluminium foil? ……………….…………………………………………………………………………..[ 1] [Total: 4]

4 A2 ‘Lean burn’ engines are a type of car engine. Table 2. 1 shows some information about lean burn engines compared to normal car engines. Table 2.1 type of engine amount of air mixed with petrol operating temperature concentration of CO in exhaust gases concentration of nitrogen oxides in exhaust gases normal less air higher higher higher lean burn more air lower lower lower (a) Suggest why lean burn engines produce lower amounts of carbon monoxide. ..………………..…………………………………………………………………………… ……………….…………………………………………………………………………..[ 1] (b) (i) State one natural process that forms nitrogen oxides. ………………..…………………….