Module 5 Unit 1 Assignment D - MODULE 5 UNIT 1 Assignment Part D 1 A compound whose empirical formula is CH 3 has a molar mass of 30 g\/mol What is its

# Module 5 Unit 1 Assignment D - MODULE 5 UNIT 1 Assignment...

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MODULE 5 UNIT 1 Assignment Part D 1. A compound whose empirical formula is CH 3 has a molar mass of 30 g/mol. What is its molecular formula? (3 points) C: 12.01g H:1.01g The empirical formula is C (12.01g) + H 3 (3.03g) = 15.04g Molar mass/empirical mass = molecular formula 30g./15.04g = 1.99 = 2 x empirical formula of CH 3 = C 2 H 6 The molecular formula is C 2 H 6 2. Find the molecular formula for each of the following compounds: (6 points) a) 30.5% nitrogen; 69.5% oxygen; molar mass of 46 g/mol N: 14.0g/mol. 30.5g/14g/mol. = 2.2 moles O: 16.0g/mol. 69.5g/16g/mol. = 4.3 moles 4.3moles /2.2moles = 1.9 = 2 to 1 ratio NO 2 is the empirical formula N (14g) + O x2 (30g) = 45g/mol. The molecular formula is NO 2 b) 2.67 g of carbon; 0.22 g of hydrogen; 7.11 g of oxygen; molar mass of 90 g/mol C: 12.01g/mole 2.67g/12.01g/mol. = 0.22 mole H: 1.01g/mole 0.22g/1.01g/mol. = 0.22 mole O: 16g/mole 7.11g/16g/mol. = 0.44 mole 0.44mol./0.22mol. = 2 = 2 to 1 ratio CHO 2 is the empirical formula with a mass of 45g/mol The molecular formula is C 2 H 2 O 4 with a molar mass of 90g Hint: Start by calculating the empirical formula.