Chem 6AH Fall 2004 Name:_______________________ Mini-Exam Chapters 1 and 2 (Wed 2) UCSD ID:______________________ Directions: You have 50 minutes to complete this exam. The first question is to be completed on this paper. On the back you will find six multiple choice questions; the answers to these go ON YOUR SCANTRON. Both this exam and the scantron are to be turned in at the end of the period. I. (15 pts) A 1.964-g sample of phosphorus is heated in oxygen; at the end of the reaction, 4.500 g of an oxide of phosphorus is obtained. The molecular weight of this material is determined to be somewhere between 130 and 150 g/mol. Calculate the empirical and molecular formula of the oxide. Multiple Choice: 6 points each 1. Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO 3 ) 2 .
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