2022 Presbyterian High Chemistry P3 (Answers)

[Turn over Name: ...................................... Register/Index Number: ............... Class: .............. PRESBYTERIAN HIGH SCHOOL SCIENCE (CHEMISTRY) 5076/3, 5078/3 Paper 3 12 August 2022 Friday 1 hour 15 minutes PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL PRESBYTERIAN HIGH SCHOOL 2022 SECONDARY FOUR EXPRESS / FIVE NORMAL (ACADEMIC) PRELIMINARY EXAMINATION INSTRUCTIONS TO CANDIDATES DO NOT OPEN THIS QUESTION PAPER UNTIL YOU ARE TOLD TO DO SO. Write your class, register number and name on all the work you hand in. Write in dark blue or black pen. Do not use correction fluid. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer any two questions. Write your answers in the spaces provided on the question paper. A copy of the Periodic Table is printed on page 13. Setter: Mr Muhammad Faeez Vetted by: Ms Chan Poh Hoon This question paper consists of 13 printed pages. For Examiner’s Use Section A Section B Total 45 20 65

2 [Turn over Section A (45 marks) Answer all questions in the spaces provided. 1 Use the list of elements below to answer the questions that follow. copper sodium chlorine aluminium nitrogen oxygen iron carbon helium bromine In your answers, you may use an element once, more than once, or not at all. Name one element which (a) is used in the manufacture of steel, iron/carbon [1] (b) can displace tin from its compound, sodium/aluminium/iron [1] (c) has six valence electrons, oxygen [1] (d) has a triple bond within its molecule, nitrogen [1] (e) is an inert gas. helium [1] 2 Zinc smelting is a process that converts zinc concentrates ( ores that contain zinc) into pure zinc. One of the last stages involves purifying zinc by fractional distillation in a column made up of silicon carbide. The main impurities in zinc are shown in Table 2.1. Pure zinc has a boiling point of 908 oC. Table 2.1 impurities boiling point /oC cadmium 765 copper 2582 iron 2887 lead 1751 (a) State why it is possible to purify zinc by fractional distillation. It has different boiling points (b) When fractional distillation is carried out, which metal will be distilled first? Cadmium (c) How would you test if the zinc purified from the fractional distillation is free from any impurities? Test the melting point to see if its