TPJC_H1Chem_08PrelimP2

TAMPINES JUNIOR COLLEGE Preliminary Examinations 2008 CHEMISTRY (Higher 1) 8872/2 PAPER 2 Thursday 21 August 2008 2 hours Additional materials: Writing Paper Graph Paper Data Booklet INSTRUCTIONS TO CANDIDATES Write your name and Civics Group on all the w ork you hand in. Write in dark blue or black pen. Section A Answer all questions in the space provided. Section B Answer two questions on separate answer paper. At the end of the examination, fasten the answers to Section B to Section A. The number of marks is given in brackets [ ] at the end of each question or part question. Question Marks Section A Name : _____________________ CG : ________ B4 B5 B6 TOTAL / 80 This document consists of 10 printed pages. [Turn over 8872_02 / 1

Section A Answer all questions in this section in the spaces provided. 1 (a) (i) On the grid given below, sketch the general trends of the first ionisation energy of the elements across the thir d period of the Periodic Tabl e. Your sketch is expected to be clear though qualitative only. Na Mg Al Si P S Cl Ar 1st ionisation energy / kJ mol–1 (ii) Explain the general trend of your sketch in (a)(i). ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ ___________________________________________________________________ [3] (b) (i) In the spaces provided, draw the elec tronic configuration of phosphorous and sulphur. phosphorous 3p 2p 3s1s 2s sulphur 3p 2p 3s1s 2s (ii) Briefly explain the relative magnitudes of the first ionisation energies of phosphorous and sulphur. ___________________________________________________________________ ___________________________________________________________________ [3] 8872_02 / 2

(c) The elements in Period 3 range from metals on the left of the per iodic table to non- metals on the right. Describe a chemical property of an oxide of magnesium which shows that it is a metal and a chemical property of an ox ide of sulphur which shows that it is a non-metal. Give chemical equations where relevant. _________________________ _____________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ______________________________________________________________________ ____________________________________________________________________ [4] (d) When diluting sulphuric acid with water, ca re must be taken because t