CHEM 1000 Test Final A - Fall 2007 - Answers

CHEM 1000 Test Final A - Fall 2007 - Answers - 1 Name: _...

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Name: ________________________ Student Number: _____________________ 1 Chemistry 1000 Final Exam – Version A Fall 2007 INSTRUCTIONS 1) Read the exam carefully before beginning. There are 19 questions on pages 2 to 12 followed by 2 pages of “Data Sheet” (including periodic table) and a blank page for any rough work. Please ensure that you have a complete exam. If not, let an invigilator know immediately . All pages must be submitted at the end of the exam. 2) If your work is not legible, it will be given a mark of zero. 3) Marks will be deducted for incorrect information added to an otherwise correct answer. 4) You may use a calculator. 5) Show your work for all calculations. Answers without supporting calculations will not be given full credit. 6) Marks will be deducted for improper use of significant figures and for answers with incorrect/missing units. 7) Do not open the exam until you are told to begin. Beginning prematurely will result in removal of your exam paper and a mark of 0. 8) You have 3 hours to complete this exam. Nobody may leave the exam room during the first hour or the last 15 minutes of the exam. Q Mark Q Mark 1 / 20 11 / 3 2 / 5 12 / 3 3 / 3 13 / 8 4 / 3 14 / 7 5 / 3 15 / 10 6 / 10 16 / 10 7 / 7 17 / 6 8 / 3 18 / 6 9 / 8 19 / 1 10 / 14 Total / 130
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Name: ________________________ Student Number: _____________________ 2 1. Fill in the blank(s). [20 marks] (a) Lanthanum has the following isotopic composition: Isotope Abundance (%) 57 138 La 0.090 57 139 99.910 Without doing any calculations, what is the approximate molar mass of La? 139 g/mol (b) Give the chemical formula for the product formed when cesium is combusted in air. CsO 2 (c) In the reaction between Cr 3+ and water, Cr 3+ is the Lewis acid and water is the Lewis base. The pH of this solution will be less than seven. (greater than, less than or approximately equal to?) (d) For each of the ions below, give the electron configuration in line notation using the noble gas abbreviation . i. Sn 2+ [Kr] 5 s 2 4 d 10 i i . S n 4+ [Kr] 4 d 10 (e) For each of the ions in part (d), indicate whether it is paramagnetic or diamagnetic. i. Sn 2+ diamagnetic i i . S n 4+ diamagnetic (f) Give the electron configuration for a neutral atom of silicon using line notation. Do not use the noble gas abbreviation. 1 s 2 2 s 2 2 p 6 3 s 2 3 p 2 (g) How many valence electrons does a neutral atom of silicon have? 4 (h) Name the allotrope of carbon that can conduct electricity. graphite (i) What is the Cl-C-Cl bond angle in CCl 4 ? 109.47° (109.5°) (j) What is the geometry of a molecule that has five atoms attached to a central atom with no lone pairs? trigonal bipyramidal What bond angle(s) would you expect to find in this molecule? 90°, 120°, 180° (90°, 120°) (k) Phosphorus has a single naturally occurring isotope. A naturally occurring neutral atom of phosphorus has 15 protons, 16 neutrons and 15 electrons. (l) Name the instrumental technique discussed in CHEM 1000 that can be used to separate different isotopes of the same element. mass spectrometry (m) What is the chemical name for the ClO 4 - ion? perchlorate 1 mark per blank
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Name: ________________________ Student Number: _____________________ 3 2. Give the name and symbol for the element which meets each description. [5 marks] Description Symbol Name The alkaline earth metal with the smallest atomic radius.
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CHEM 1000 Test Final A - Fall 2007 - Answers - 1 Name: _...

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