Download Formulas, Equations and Moles - General College Chemistry I - Worksheet | CHEM 112 and more Assignments Chemistry in PDF only on Docsity! Chemistry 112 Worksheet — Formulas, Equations, and Moles Harwood KEY 1. The following diagram shows A (closed circles) reacting with B (open circles). Write a balanced chemical equation describes the stoichiometry of the reaction depicted in the diagram A2 + B2 → 2AB 2. How many moles does each of the following samples contain? a. 1.0 g of lithium (1.0 g)(1 mol / 6.941 g) = 0.14 mol b. 1.0 g of nitrogen gas (nitrogen gas exists as N2) (1.0 g)(1 mol / 28.0134 g) = 0.036 mol c. 1.0 g of penicillin G potassium, C16H17N2O4SK (1.0 g)(1 mol / 372.4856 g) = 0.0027 mol 3. What is the empirical formula of stannous fluoride, a compound added to toothpaste to protect teeth against decay? Its mass percent composition is 24.25% F, 75.75% Sn. mol F = (24.25 g)(1 mol / 18.9984 g) = 1.27642 mol F mol Sn = (75.75 g)(1 mol / 118.710 g0 = 0.638101 mol Sn F: 1.27642 mol / 0.638101 mol = 2 Sn: 0.638101 mol / 0.638101 mol = 1 Empirical formula = SnF2 4. Disilane, Si2Hx , is analyzed and found to contain 90.28% by mass silicon. What is the value of x? Mass of Si = 90.28 g per 100 g sample Mass of H = 100.00 g - 90.28 g = 9.72 g mol Si = (90.28 g)(1 mol / 28.0855 g) = 3.21447 mol mol H = (9.72 g) (1 mol / 1.0079 g) = 9.643814 mol Si: 3.21447 mol / 3.21447 mol = 1 H: 9.643814 mol / 3.21447 mol = 3 x = 3 5. How many grams of the dry-cleaning solvent ethylene chloride, C2H4Cl2, can be prepared by reaction of 15.4 g of ethylene, C2H4, with 3.74 g of Cl2? C2H4 + Cl2 → C2H4Cl2 mol ethylene = (15.4 g)(1 mol / 28.0536 g) = 0.5489 mol mol chlorine = (3.74 g)(1 mol / 70.906 g) = 0.05274 mol maximum mol ethylene chloride formed from all ethylene: mol = (0.5489 mol C2H4)(1 mol C2H4Cl2 / 1 mol C2H4) = 0.5489 mol C2H4Cl2 mol = (0.05274 mol Cl2)(1 mol C2H4Cl2 / 1 mol Cl2) = 0.05274 mol C2H4Cl2 So 0.05274 mol C2H4Cl2 will be formed. mass C2H4Cl2 = (0.05274 mol)(98.9596 g / 1 mol) = 5.22 g C2H4Cl2
