2811_Jun_02MS

2811_Jun_02MS - OCR Advanced Subsidiary GCE in Chemistry...

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OCR Advanced Subsidiary GCE in Chemistry 2811 June 2002 Chemistry Foundation Page 1 of 7 3882 June 2002 Final Jun2002MS.doc 07/06/2002 Subject: Chemistry Foundation Code: 2811 Session: June Year: 2002 Final Mark Scheme 02/6/2002 MAXIMUM MARK 60
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OCR Advanced Subsidiary GCE in Chemistry 2811 June 2002 Chemistry Foundation Page 3 of 7 3882 June 2002 Final Jun2002MS.doc 07/06/2002 Abbreviations, annotations and conventions used in the Mark Scheme / = alternative and acceptable answers for the same marking point ; = separates marking points NOT = answers which are not worthy of credit ( ) = words which are not essential to gain credit = (underlining) key words which must be used to gain credit ecf = error carried forward AW = alternative wording ora = or reverse argument 1. (a) ( Atoms of) the same element / with same protons. ... with different masses/different numbers of neutrons 9 [1] (b) number of isotope percentage composition protons neutrons 191 Ir 38% 77 114 193 Ir 62% 77 116 9 9 9 Accept 37-39% for 191 Ir; 61-63% for 193 Ir but must add up to 100. [3] (c) (i) average atomic mass/weighted mean/average mass 9 compared with carbon-12 9 1/12th of mass of carbon-12 / on a scale where carbon-12 is 12 9 mass of 1 mole of element/mass of 1 mole of carbon-12 is equivalent to first two marks
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This note was uploaded on 10/20/2011 for the course ECON 03 taught by Professor Mark during the Winter '08 term at UCLA.

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2811_Jun_02MS - OCR Advanced Subsidiary GCE in Chemistry...

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