ACSI 2020 Y6 Prelim Paper 2_QP

Anglo-Chinese School (Independent) YEAR 6 PRELIMINARY EXAMINATION 2020 INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAMME CHEMISTRY HIGHER LEVEL Paper 2 Monday 14 September 2020 2 hours 15 minutes INSTRUCTIONS TO CANDIDATES • Write your candidate number in the box above. • Do not open this examination paper until instructed to do so. • Answer all questions. • A calculator is required for this paper. • A copy of the Chemistry Data Booklet is required for this paper. • Write your answers in the boxes provided. • The maximum marks for this examination paper is 90 marks. For examiner’s use Qn 1 /5 Qn 2 /9 Qn 3 /9 Qn 4 /16 Qn 5 /7 Qn 6 /11 Qn 7 /10 Qn 8 /11 Qn 9 /4 Qn 10 /8 Wrong s.f. /units Total /90 ________________________________________________________________________ This question paper consists of 22 printed pages including this cover page. Candidate Number Candidate Full Name

2 Answer all questions. Write your answers in the boxes provided. 1. Known for its silver, shiny appearance, chromium is used to coat cars, stoves and other appliances to protect them from corrosion and to improve their looks. (a) Mass spectroscopic analysis of a sample of chromium gave the following results: Isotopes in the sample 50Cr 52Cr 53Cr 54Cr Percentage abundance 4.25 83.05 9.90 2.80 (i) Calculate the relative atomic mass of this sample of chromium to two decimal places. [2] ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (ii) Write the electronic configuration of chromium. [1] ....................................................................................................................................... (b) Sketch a graph to show the changes in Log10 IE, ionisation energy, as the first 8 electrons of a chlorine atom are successively removed. [2] Log10 IE Number of electrons removed 1 2 3 4 5 6 7 8

3 Electron domain geometry Molecular geometry Nitrogen …………………………………… …………………………………… Carbon …………………………………… Trigonal planar (This question continues on the following page) 2. (a) The structural formula of ethanediamide is shown. Predict the electron domain and molecular geometries at the nitrogen and carbon atoms, applying the VSEPR theory. [3] (b) (i) Suggest one reason why ethanediamide is a solid and ammonia is a gas at room temperature. [1