CHEM 201 Lecture 11: CHEM 201 - Lecture 11
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Chapter 3, pages: 98-109: determination empirical (simplest) and molecular formula. Example: determine the empirical and molecular formula of a compound composed of 72. 4% fe, and. 27. 6% o by mass if molar mass of this compound is 231. 4 g/mol: convert percent of each element to a mass: 55. 85 g 16. 00 g: find the mole ratio of the elements: Fe(1. 30/1. 30) o(1. 73/1. 30) = fe1o1. 33: if subscripts are fractional quantities multiply all the subscripts by small numbers to convert all the subscripts to whole numbers. Fe(1 3)o(1. 33 3) = fe3o4- empirical formula: to establish a molecular formula we need: Integral factor = 231. 4 g/mol: 231. 4 g/mol= 1. Exercise # 1 an organic compound (molar mass = 200. g/mol) has 71. 95% c, 12. 08%h and 15. 97% o by mass. Determine simplest and molecular formulas of this compound. 1. convert percent of each element to a mass: To establish molecular formula find the integral factor:
