Chem 1211 1st Edition Lecture 11 Outline of Last Lecture I. Oxidation-Reduction ReactionsII. Stoichiometry Outline of Current Lecture I. Stoichiometry ContinuedII. Limiting ReagentsIII. Info for StoichiometryCurrent LectureI. Stoichiometry Continueda. ConcepTest: For the reaction Cl2 (g) + H2 (g) 2 HCl (g), how many grams of HCl are produced from 7.09 grams of chlorine gas? i. ANSWER: 7.29 gramsii. Reasoning: convert 7.09 grams Cl2 to grams HCl by multiplying (7.09g Cl2) x(1 mol Cl2/70.9 g Cl2) x (2 mol HCl/ 1 mol Cl2) x (36.458 g HCl/ 1 mol HCl)b. ConcepTest: For the reaction 4 NH3 + 5 O2 4 NO + 6 H2O, if 17 g of ammonia reacts, how many moles of hydrogen atoms are contained in the products? i. ANSWER: 3 moles of Hii. 17g NH3x(1 mol/ 17g NH3)x(6 mol H2O/4 mol NH3)x(2 mol H/1 mole H2)c. Calculation Strategy i. Mass of moles (use formula weight)ii. Ration of moles (use stoichiometric coefficients)iii. Moles to mass (use formula weight) d. ConcepTest: Consider the reaction Zn + 2 HCl ZnCl2 + H2. If 65.4 g of Zn reacts with 36.5 g of HCl, what is the total mass of the ZnCl2 and H2?i. ANSWER: .692 gii. For every one Zinc, you need two HCl. Since we only have one mole of HCl, only half of the zinc will react. This is an example of a limiting reagent.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. Limiting Reagents a. ConcepTest: Consider the reaction Zn + 2 HCl ZnCl2 + H2. Which case has zinc as the limiting reaction?i. 1 mol Zn, 1 mol HClii. 1.5 mol Zn, 2 mol HCliii. .5 mol Zn, 2 mol HCliv. 2 mol Zn, 1 mol HClv. 1 mol Zn, 2 mol HCl1. ANSWER: iii (.5 mol Zn, 2 mol HCl)2. Reasoning: You need a 1:2 ratio, but iii has a 1:4 ratioIII. Info for Stoichiometrya. Some information comes from experimentsi. Formulaii. Ratios of reagentsb. Quantitative analysis (chemical analysis) - use known reaction, known amounts of one substance to determine another c. Combustion analysis- burn known amount and analyze carbon, hydrogen, and other atoms d. ConcepTest: Which empirical formula corresponds to a molecule that has the formula weight of 88? i. CHii. CH2iii. CH2Oiv. C2H4Ov. None of these 1. ANSWER:
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