workshop 4 f10 key

workshop 4 f10 key - -3 moles XBr 2 XBr 2 mw is...

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Workshop 4 1) Adapted from Exam 1, Fall 2007 (15 pts) A sample of a substance with the chemical formula XBr 2 (where X stands for an unknown cation of charge +2) weighs 0.5000 g. The substance is reacted with silver nitrate according to: XBr 2 + 2AgNO 3 2AgBr + X(NO 3 ) 2 The silver bromide produced is a solid and is found to weigh 1.0198 g. What is the atomic mass of X and which element is it? (Hint: you will need all the significant figures available) Have 5.430x10 -3 moles AgBr, so have 2.715 x10
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Unformatted text preview: -3 moles XBr 2 XBr 2 mw is 0.5000/2.715 x10-3 = 184.16g/mol X is Mg 2) Adapted from Exam 1, Fall 2005 What if I want to make 130 grams of iodine pentafluoride and I know the reaction proceeds with a 83% yield. How many grams of iodine and fluorine should I start with? 130g actual yield => 156g theoretical yield=> 0.706 moles iodine pentafluoride => 1.76 moles fluorine and 0.353 moles iodine => 66.9g fluorine and 89.6g iodine...
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