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Organic Chemistry 2243 Final Study GuideCHAPTER 1Organic Chemistry- The chemistry of carbon1. Officially defined in the 19th century Vital Force Theory- The Theory: we might call an organic chemical came from a living organism1. This was proven dead wrong when ammonium cyanide (an inorganic compound) was heated and urea (an organic compound) was produced Organic molecules can be made from a non-natural or non-living sourceCHAPTER 2Bronsted Lowry Acids and Bases- Acid- a material that releases a proton or a hydrogen atom- Base- a material that donates a hydroxide ion(OH-)Bronsted Lowry Acid- donates a protonBronsted Lowry Base- accepts a protonThe Citrerion for acid strength is the extent of ionization in water- Strong acids ionize extensively- Mineral Acid: HCl, HBr, HI, H2SO4, HNO3, and HClO are Hl strongCommon Strong Bases: NaOH, KOH, LiOH, Mg(OH)2, Ca(OH)2, and Ba(OH)2 - Strong bases are extensively ionized in waterEquilibrium- 2 chemical reactions in competition- To determine the position of the equilibrium(k), we must consider both reactions (on either sideof the arrow) - Typically, the acid and base are on the left side of the equation and the conjugate acid and base are on the right side because the reaction is carried out to the leftWeak Acids- React reversibly with water to form H3O+1. They contain ionizable hydrogen atoms like nitrous acid (HNO2)2. They contain cations like ammonium (NH4+)Weak Bases- Solutes that react with water molecules to quire H+ and leave a hydroxide ion (OH-) behind1. Examples are ammonia and waterOther Solvents- Solvents other than water are required to put organic acids or bases into solution1. This “other solvent” is usually another organic compound Diethyl ether, hexane, and dichloromethane are common solventsBy changing the base, it is possible to change the relative acidity of the acidLewis Definitions of Acids and Bases- These definitions are more general and focus on the transfer of electrons1. Electron rich atoms donate to electron poor atoms2. A Lewis acid will donate electron pairs to anything EXCEPT hydrogen and carbon- Electrons flow from the base to the acid- acids do NOT donate electrons- Lewis Acid- electron pair acceptor- Lewis Base- Electron pair donor- Ate complex: a reaction between a Lewis acid and base by adding on a 4th bondThere is no such thing as a free proton- H+ will not exist by itself and is always connected to somethingThe strength of the H-X bond is important- The weaker the bond, the stronger the acid and the easier it is to pull offMore stable=Less reactiveLess Stable=More reactiveElectronegativity- A property of an atom, its ability to attract electrons- This property increases from left to right on the periodic table and decreases going down the periodic table1. Up and Down: Size is more important than electronegativity2. Left to right: Electronegativity is more important than size- More electronegative atoms will hold tightly onto their electrons and be unwilling to donateWhy is HI more acidic then HF?- I- and F- are located on top of each other on the periodic table, meaning that the focus should beon size rather than electronegativity- Since I is a lot bigger then F, the electron density of the two electrons, while equal, is more dispersed/spread out on I. Because of this, the bond between the electrons and the nucleus andis weaker, making I more reactive/acidic- The electrons on F are more localized, making them easier to locate and donate (a better base)Strong Acid=Weak Conjugate BaseWeak acid= Strong Conjugate BaseMore Electronegative Atom:- Will hold electrons tightly so that they may not be donated- Are less reactive- Are weak basesResonance- charge dispersal over multiple atoms, making the atom more stableSigma and Pi bonds- Sigma bond- the strongest bond because it has maximum overlap of orbitals- Pi bond- weaker because there is shared electron \density between parallel adjacent p-orbitalsWhy is H2SO4 is more acidic then HSO4- The charge is dispersed over a greater area on the perchlorate anion1. The greater the charge dispersion, the more stable the ion isImportant Lewis Acids:- Boron Tetraflouride (BF3)- Aluminum Chloride (AlCl3)- Mercuric Chloride (HgCl2)CHAPTER 3Ionic Bond- Displacement of electrons through chemical reactions- The molecule is formed by breaking a bond to generate a positive or negative charge since it willhave a counterion with an opposite charge- Atoms in the outer groups will form ionic bondsIonization Potential- the energy required for the loss of one electron from one atom2nd Ionization potential- the energy required to lose 2 electrons3rd ionization potential- the energy required to lose 3 electronsElectron affinity- the energy required for the gain of one electronBond Strength- Reefers to the ease of making/breaking bonds in a chemical reaction- Focuses on reactivity/polarityRules of NomenclatureFunctional Groups- collection of atoms with unique propertiesSubstituents- branches off of the parent chain- called alkyl group, suffix: -ylSuffixes are indicative of functional groupsPrefixes:1=meth 4=but 7=hept2=eth 5=pent 8=oct3= prop 6=hex 9=nonaAssign Numbers to the carbons and give substituents the lowest numbers possibleMore than one substituent? Use Prefixes:2=di, 3=tri, 4=tetra, 5=pentaUse commas to separate numbers and dashes to separate numbers- Ex: 2,4,5-trimethylnonaneIf there are different alkyl groups (like methyl and ethyl) put the names in alphabetical orderAlkanes- Carbons attached in long unbranched chains- Suffix: -aneHalogens- No Suffix- Treated like substituents- Drop the –ine ending and add –o as the endingCyclic Alkanes- When alkanes form rings of carbon atoms- General Formula- CnH2n- Based off the number of carbons- Use the prefix cyclo- to denote as a ringSubstituents- Take the name of the ring and are treated as an alkyl substituent- Give the lowest number possible or lowest combination of numbersRings and Chains- One has to be labeled as the parent, one to be labeled as a substituent1. 7 or more carbons in the chain- the chain is the parent2. 6 or fewer in the chain- the ring is the parent3. If equal in numbers- can choose either one- The ring is attached to the chain by a substituent Alkenes- General Formula- CnH2n- Contains 1 pi bond and 3 sigma bonds (one double bond)- Suffix= -ene- Must denote the position of the double bond, give it the lowest number possible (takes priority in naming- The longest chain contains the C=C


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UConn CHEM 2443 - Final Study Guide

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