• Study Resource
  • Explore Categories
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
CH 17 Study Guide with answer Key
CH 17 Study Guide with answer Key

... aqueous solutions are mixed together. First, calculate the concentrations of the ions in the final solution. Use the solubility product constant expression to calculate the ion product (Qsp ) for the substance that might precipitate. Compare the result with the Ksp of the substance. 7. What can you ...
Chem 2A Final Review
Chem 2A Final Review

... 57. Which species (elements) are oxidized and which are reduced in the following reaction. a) Zn + CuCl2  ZnCl2 + Cu b) 3H2S + 2HNO3  3S + 2NO + 4H2O c) 2FeBr3  2FeBr2 + Br2 ...
Metals Minitest
Metals Minitest

... Polymerisation is the process in which the small monomer units join together to form a large polymer molecule. c) Addition polymerisation Addition polymerisation is a process involving many small, unsaturated monomers combining to form one large polymer molecule. The alkenes ethene and propene are t ...
National 5 Chemistry Unit 3 Chemistry In Society
National 5 Chemistry Unit 3 Chemistry In Society

... Polymerisation is the process in which the small monomer units join together to form a large polymer molecule. c) Addition polymerisation Addition polymerisation is a process involving many small, unsaturated monomers combining to form one large polymer molecule. The alkenes ethene and propene are t ...
Chapter 8 Thermochemistry
Chapter 8 Thermochemistry

... 3. The phases of all reactant and product species must be stated 4. The value of ΔH applies when products and reactants are at the same temperature, usually 25 °C ...
Heat
Heat

... temperature. Write the reaction: o NH4NO3 + H2O + Heat →NH41+ (aq) + NO31- (aq) o NH4NO3 is used in cold packs for sports injuries. o ENDOTHERMIC Reaction o Note: NH4NO3 can also undergo an EXOTHERMIC reaction when it explodes, hence its use as a blasting agent in mining and (unfortunately) in terro ...
C5H12 + 8 O2 → 5 CO2 + 6 H2O
C5H12 + 8 O2 → 5 CO2 + 6 H2O

... Oxidation numbers always change in redox reactions! Example: Balance the reaction between solid lead (II) oxide and ammonia gas to produce nitrogen gas, liquid water, and solid lead. ...
Chemical Kinetics
Chemical Kinetics

... Integrated first-order rate law is ln[A] = kt + ln[A]o 1. The equation shows how [A] depends on time. 2. Is in the form y=mx + b, where a plot of y vs. x is a straight line with slope m and ...
Chapter 8 Thermochemistry
Chapter 8 Thermochemistry

... Chapter 8 Thermochemistry Thermochemistry refers to the study of the heat flow that accompanies chemical reactions. Heat is a particular form of energy that is transferred from a body at a high temperature to one at a lower temperature when they are brought into contact with each other. ...
Oxidation-Reduction Processes in Natural Waters
Oxidation-Reduction Processes in Natural Waters

... Organisms catalyze all significant redox reaction in natural waters. As illustrated in the table, with the exception of photosynthesis and hydrogen generation, all of the reactions in the table are thermodynamically favorable as written. That is, the reactions as written have a negative free energy. ...
FORMULA WRITNG
FORMULA WRITNG

... 5) Manganese (III) phosphate ____________ 4. Draw Lewis dot structures for each of the following compounds. (Remember that the structures for ionic compounds must include charges for any ions and covalent compounds must have any shared electrons encircles or represented by a bond.) a. BeF2 ...
IChO 2012
IChO 2012

21:3 Classifying Chemical Reactions
21:3 Classifying Chemical Reactions

... Yeast is a microscopic, one-celled organism belonging to the group of organisms called fungi. There are many kinds of yeasts, some of them of great importance to humans. Yeast is necessary to make leavened bread, beer, and cheese. It is rich in B vitamins; a form of yeast called brewer's yeast is us ...
Final Study Guide (Semester 2) Answer Key
Final Study Guide (Semester 2) Answer Key

... ***The first thing you should do when solving this is look at the common ion chart and write down all the ions. It’s much easier than looking them up again for each question. a. Write the balanced molecular equation. Include phase symbols. Ba(NO3)2(aq) + K2SO4(aq) BaSO4(s) + 2KNO3 (aq) Switch the c ...
thermdyn - chemmybear.com
thermdyn - chemmybear.com

... chloride. Indicate whether each factor makes the (a) When liquid water is introduced into an evacuated reaction for the formation of sodium chloride from vessel at 25C, some of the water vaporizes. Preits elements more or less exothermic. dict how the enthalpy, entropy, free energy, and temperature ...
Industrial Chemistry - Deans Community High School
Industrial Chemistry - Deans Community High School

... Pharmaceutical Industry Drugs alter the biochemical processes in our bodies, for example, changing the way we feel and behave. Drugs which lead to an improvement in health are called medicines. Once a new drug is discovered, it will be patented, the licence lasting 20 years. Many years of trials ma ...
Advanced Placement Chemistry Test
Advanced Placement Chemistry Test

... equilibrium at 1000 K. Determine whether the equilibrium concentration of HI(g) will be greater than, equal to, or less than the initial concentration of HI(g). Justify your answer. {3 marks} ...
Problem 5. The Second Law of thermodynamics
Problem 5. The Second Law of thermodynamics

... 2. Suppose you detect a signal from a particular 1μm2 area. The probability to have one particle within this area is 0.035. For two particles such probability is (0.035)2 and for three it is equal to (0.035)3 etc. The probability that the detected signal originates from a single Au nanoparticle is: ...
Problem 5. The Second Law of thermodynamics
Problem 5. The Second Law of thermodynamics

Every reaction is reversible: A chemical reaction is in equilibrium
Every reaction is reversible: A chemical reaction is in equilibrium

... This particular equilibrium constant, K, is known as the Partition Coefficient. It depends on the two immiscible liquids involved, the solute and the temperature. Iodine is much more soluble in Methylbenzene than in Water. The value of the partition coefficient is quite high. Solvent extraction is a ...
CIS Exam Questions
CIS Exam Questions

... A Increases the rate of the forward reaction only B Increases the rate of the reverse reaction only C Increases the rate of both the forward and reverse reactions D Changes the position of the equilibrium of the reaction 2. In which of the following systems will the equilibrium be unaffected by a ch ...
The Gibbs Function of a Chemical Reaction*
The Gibbs Function of a Chemical Reaction*

... place. They are usually not elementary processes, but rather only some average resulting reaction from a series of elementary steps comprising a mechanism. Stoichiometric equations are helpful for accounting purposes only as required in stoichiometric calculations. This is much the same as using sym ...
Unit 3 Exam Level Questions
Unit 3 Exam Level Questions

... A Increases the rate of the forward reaction only B Increases the rate of the reverse reaction only C Increases the rate of both the forward and reverse reactions D Changes the position of the equilibrium of the reaction 2. In which of the following systems will the equilibrium be unaffected by a ch ...
File - wilson science WEBSITE
File - wilson science WEBSITE

ch16powerpoint
ch16powerpoint

... • P.6 Cyclopropane is the smallest cyclic hydrocarbon. Because its 600 bond angles allow poor orbital overlap, its bonds are weak. As a result, it is thermally unstable and rearranges to propene at 10000C via a first-order reaction: • The rate constant is 9.2s-1; (a) What is the half-life of the rea ...
< 1 ... 85 86 87 88 89 90 91 92 93 ... 185 >

Lewis acid catalysis



In Lewis acid catalysis of organic reactions, a metal-based Lewis acid acts as an electron pair acceptor to increase the reactivity of a substrate. Common Lewis acid catalysts are based on main group metals such as aluminum, boron, silicon, and tin, as well as many early (titanium, zirconium) and late (iron, copper, zinc) d-block metals. The metal atom forms an adduct with a lone-pair bearing electronegative atom in the substrate, such as oxygen (both sp2 or sp3), nitrogen, sulfur, and halogens. The complexation has partial charge-transfer character and makes the lone-pair donor effectively more electronegative, activating the substrate toward nucleophilic attack, heterolytic bond cleavage, or cycloaddition with 1,3-dienes and 1,3-dipoles.Many classical reactions involving carbon–carbon or carbon–heteroatom bond formation can be catalyzed by Lewis acids. Examples include the Friedel-Crafts reaction, the aldol reaction, and various pericyclic processes that proceed slowly at room temperature, such as the Diels-Alder reaction and the ene reaction. In addition to accelerating the reactions, Lewis acid catalysts are able to impose regioselectivity and stereoselectivity in many cases.Early developments in Lewis acid reagents focused on easily available compounds such as TiCl4, BF3, SnCl4, and AlCl3. The relative strengths of these (and other) Lewis acids may be estimated from NMR spectroscopy by the Childs method or the Gutmann-Beckett method. Over the years, versatile catalysts bearing ligands designed for specific applications have facilitated improvement in both reactivity and selectivity of Lewis acid-catalyzed reactions. More recently, Lewis acid catalysts with chiral ligands have become an important class of tools for asymmetric catalysis.Challenges in the development of Lewis acid catalysis include inefficient catalyst turnover (caused by catalyst affinity for the product) and the frequent requirement of two-point binding for stereoselectivity, which often necessitates the use of auxiliary groups.
  • studyres.com © 2026
  • DMCA
  • Privacy
  • Terms
  • Report