Name ________________________________________ Class _________________ Date _______________
Two students prepared aspirin according to the following reaction in which aceticanhydride, C4H6O3, reacts with salicylic acid, C7H6O3, to form aspirin, C9H8O4, andacetic acid, C2H4O2.
The procedure involved heating the reaction mixture in a water bath for 15 minutes at75 ЊC, not to exceed 80 °C. The mixture was removed from the water bath and distilledwater was added to decompose any unreacted acetic anhydride. The mixture was thenplaced in an ice bath for 5 minutes to facilitate the formation of aspirin crystals. Theaspirin crystals were collected using filtration. The aspirin crystals were dried and
then transferred to a watch glass and massed. Because their grades were partially based on accuracy, both students used their verybest lab technique. Which student got the better grade and why?
1. Determine the molar masses of: a. acetic anhydride, C4H6O3. b. salicylic acid, C7H6O3. c. aspirin, C9H8O4.
Name ________________________________________ Class _________________ Date _______________
2. How many moles of salicylic acid were added to the reaction mixture? 3. Given the density of acetic anhydride to be 1.05 g/mL, what was the mass of the
acetic anhydride added to the reaction? How many moles of acetic acid wereadded?
4. According to the mole ratios in the given reaction, what is the limiting reagent 5. What is the theoretical yield, in grams, of aspirin in each reaction? 6. What was the actual yield, in grams, of aspirin in each reaction? 7. What was the percent yield in each reaction? 8. Evaluate your answers. Which student got the better grade and why?
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13: Balancing Chemical Equations
14: Single-Replacement Reactions
15: Double-Replacement Reactions
21: Kinetic Energy and Temperature
23: The Manometer and Vapor Pressure
30: Pressure-Volume Relationship for a Gas
34: Development of Atomic Models
39: Emission Spectrum of an Element
42: Periodic Table of the Elements (a)
43: Periodic Table of the Elements (b)
47: Atomic Radius vs. Atomic Number
59: Electrolytes and Nonelectrolytes
62: Concentrated and Dilute Solutions
64: Activation Energy and Catalysts
65: Reversible Reactions and Equilibrium
67: Heat, Entropy, and Free Energy
69: Dissociation of Weak and Strong Acids
70: Oxidation-Reduction Reactions
72: Voltaic and Electrolytic Cells
Section Review 1.2: Chemistry Far and Wide
Section Review 1.3: Thinking Like a Scientist
Section Review 1.4: How to Study Chemistry
Section Review 2.3: Elements and Compounds
Section Review 2.4: Chemical Reactions
Section Review 3.1: The Importance of Measurement
Section Review 3.2: Uncertainty in Measurement
Section Review 3.3: International System of Units
Section Review 4.1: What Do I Do Now?
Section Review 4.2: Simple Conversion Problems
Section Review 4.3 More-Complex Problems
Ch. 5: Atomic Structure and the Periodic Table
Section Review 5.2: Structure of the Nuclear Atom
Section Review 5.3: Distinguishing Between Atoms
Section Review 5.4: The Periodic Table: Organizing the Elements
Section Review 6.1: Introduction to Chemical Bonding
Section Review 6.2: Representing Chemical Compounds
Section Review 6.3: Ionic Charges
Section Review 6.4: Ionic Compounds
Section Review 6.5: Molecular Compounds and Acids
Section Review 6.6: Summary of Naming and Formula Writing
Section Review 7.1: The Mole: A Measure of Matter
Section Review 7.2: Mole-Mass and Mole-Volume Relationships
Section Review 7.3: Percent Composition and Chemical Formulas
Section Review 8.1: Describing Chemical Change
Section Review 8.2: Types of Chemical Reactions
Section Review 8.3: Reactions in Aqueous Solutions
Section Review 9.1: The Arithmetic of Equations
Section Review 9.2: Chemical Calculations
Section Review 9.3: Limiting Reagent and Percent Yield
Section Review 10.1: The Nature of Gases
Section Review 10.2: The Nature of Liquids
Section Review 10.3: The Nature of Solids
Section Review 10.4: Changes of State
Ch. 11: Thermochemistry--Heat and Chemical Change
Section Review 11.1: The Flow of Energy-Heat
Section Review 11.2: Measuring and Expressing Heat Changes
Section Review 11.3: Heat in Changes of State
Section Review 11.4: Calculating Heat Changes
Section Review 12.1: The Properties of Gases
Section Review 12.2: Factors Affecting Gas Pressure
Section Review 12.3: The Gas Laws
Section Review 12.4: Ideal Gases
Section Review 12.5: Gas Molecules: Mixtures and Movements
Section Review 13.1: Models of the Atom
Section Review 13.2: Electron Arrangement in Atoms
Section Review 13.3: Physics and the Quantum Mechanical Model
Section Review 14.1: Classification of the Elements
Section Review 14.2: Periodic Trends
Ch. 15: Ionic Bonding and Ionic Compounds
Section Review 15.1: Electron Configuration in Ionic Bonding
Section Review 15.2: Ionic Bonds
Section Review 15.3: Bonding in Metals
Section Review 16.1: The Nature of Covalent bonds
Section Review 16.2: Bonding Theories
Section Review 16.3: Polar Bonds and Molecules
Section Review 17.1: Liquid Water and Its Properties
Section Review 17.2: Water Vapor and Ice
Section Review 17.3: Aqueous Solutions
Section Review 17.4: Heterogeneous Aqueous Systems
Section Review 18.1: Properties of Solutions
Section Review 18.2: Concentrations of Solutions
Section Review 18.3: Colligative Properties of Solutions
ITA – Computer Science Division – BrazilIt is suggested here an algorithm based on stickers for the DNAComputing model [16] that solves the well known Bin-Packing Prob-lem (BPP), that belongs to the class N P-Hard in the strong sense,in a time bounded by O(n2q), where n is the quantity of items and qthe space requirements expressed in bits. To the best of the authors’ knowledge, this is t
Federal Register / Vol. 71, No. 116 / Friday, June 16, 2006 / Notices and resultant under-utilization; Form Number: CMS–R–52 (OMB#: 0938– 0386); Frequency: Recordkeeping and Reporting—Annually; Affected Public: Michelle Shortt, Business or other for-profit and Federal government; Number of Respondents: Director, Regulations Development Group, Office of Strategic Op