held but untouched.

Carboxylic acids have the highest priority, always named by adding -oic acid to the alkyl root.

Cyclic carboxylic acids are named as cycloalkanes carboxylic acids.  Salts of carboxylic acids are named with the cation, followed by the acid with the ending -oate.

Dicarboxylic acids are molecules with two carboxyl groups.  The first six straight-chain terminal dicarboxylic acids are:

Oxalic/ethanedioic acid (2C)

Malonic/propanedioic acid (3C)

Succinic/butanedioic acid (4C)

Glutaric/pentanedioic acid (5C)

Adipic/hexanedioic acid (6C)

Pimelic/heptanedioic acid (7C)

Carboxylic acids are polar and form hydrogen bonds with one another at two different points.  As a result, carboxylic acids form dimers.

Acidity of carboxylic acids is due to resonance stabilization of the carboxylate anion.

Electron-withdrawing groups, such as -Cl or -NO₂, as substituents on carbon atoms near the carboxyl group further absorb the negative charge and increase acidity.

Electron-donating groups, such as -NH₂ or -OCH₃, donate additional electron density and destabilize the negative charge, making the compound less acidic.

In dicarboxylic acids, one -COOH influences the other, making the compound more acidic than a monocarboxylic acid.  Once the proton leaves, and the carboxylate anion has formed, the second carboxyl group is less acidic.

Beta dicarboxylic acids have highly acidic α-hydrogens locate on the carbon between the two carboxyl groups.  Loss of this acidic hydrogen atom produces a carbanion that is stabilized by the electron-withdrawing effect of two carboxyl groups.

Carboxylic acids can be prepared via oxidation of aldehydes, primary alcohols and certain alkylbenzene.  The oxidant is usually potassium permanganate, KMnO₄.

Organometallic reagents, such as Grignard reagents, react with CO₂ to form carboxylic acids, and are useful for the conversion of tertiary alkyl halides.

The cyanide anion (-C≡N) carries the negative charge on the carbon atom, making it a great nucleophile but not a great base.

It will displace primary and secondary halides in SN2.  Nitriles can then be hydrolyzed under either acidic or basic conditions, producing carboxylic acids and ammonia.

Aldehydes are named with the suffix -al.

Common names of the first five aldehydes: formaldehyde, acetaldehydel, propionaldehyde, butyraldehyde and valeraldehyde.

If an aldehyde is attached to a ring, the suffix -carbaldehyde is used.  If the aldehyde does not hold priority in the molecule, it is named with the prefix formyl-.

  (cyclopentanecarbaldehyde)

   (m-formylbenzoic acid)

Ketones are named with the suffix -one and must be specified with a number, with the exception of propanone (acetone), butanone and cyclic ketones.

When a ketone is a substituent, the prefix oxo- is used.

(3-oxobutanoic acid)

(cyclopentanone)

The dipole moments associated with polar carbonyl groups can line up, causing an elevation in boiling point.

Even though the dipoles are more polar than alcohols, the elevation in boiling point is less than that in alcohols because no hydrogen bonding is involved.

Aldehydes are more reactive towards nucleophiles than ketones.

An aldehyde can be obtained from the partial oxidation of a primary alcohol (using PCC). A ketone can be obtained from the oxidation of a secondary alcohol (using sodium or potassium dichromate, chromium trioxide (Jone's reagent or PCC).

Double bonds can be oxidatively cleaved to form aldehydes and/or ketones using ozone (review multiple bonds).

Friedel-Crafts acylation produces aromatic ketones or aldehydes in the form of R-CO-Ar.

Aldehydes and ketones exist in solution as a mixture of two isomers, the familiar keto form and the enol form, representing the unsaturated alcohol.

The two isomers, which differ only in the placement of a proton and double bond, are called tautomers.  There are many more keto-isomers than enol-isomers in solution.

The process of interconverting is called enolization or, less specifically, tautomerization.

The enolate carbanion, which acts as a nucleophile, can be created with a strong base, such as lithium diisopropyl amide (LDA or potassium hydride (KH).

A 1,3-dicarbonyl is extra acidic due to the two carbonyls and is often used to make the carbanion.  Once formed, the nucleophilic carbanion reacts via SN2 with alkyl halides in Michael additions.

The carbanion attaches to the unsaturated carbonyl at the β-position owing to its resonance forms.

(TODO: Picture.)

The C=O bond is polarized, making the carbon an electrophile for addition reactions.

When a nucleophile attacks, it forms a covalent bond to the carbon, breaking the π bond in the C=O.  The electrons from the π bond are pushed up onto the oxygen atom, generating a tetrahedral intermediate.

If no good leaving group is present, the carbonyl will not re-form and the final product will be nearly identical to the intermediate except that the -O⁻ will usually accept a proton to become a hydroxyl (-OH) group.

If a good leaving group is present, the carbonyl double bond can re-form and push off the leaving group.

(TODO: Pictures.)

In the presence of water, aldehydes and ketones react to form gem-diols (1,1-diols).

Nucleophilic oxygen in water attacks the electrophilic carbonyl carbon.  This hydration reaction proceeds slowly but the rate can be increased by adding a small amount of acid or base.

(TODO: Pictures.)

When one equivalent of alcohol, which acts as the nucleophile, is added to an aldehyde or ketone, the product is a hemiacetal or a hemiketal.

When two equivalents of alcohol are added, the reaction proceeds all the way and the product is an acetal or a ketal.

Hydrogen cyanide (HCN) is a classic nucleophile and is acidic due to is triple bond and electronegative nitrogen atom.

After the hydrogen dissociates, the nucleophilic cyanide anion attacks the carbonyl carbon atom.

Reactions with aldehydes and ketones produce cyanohydrins (once the oxygen is reprotonated).  The cyanohydrin gains its stability from the newly formed C-C bond.

Ammonia, a good nucleophile, reacts readily with carbonyls.

In the simplest case, ammonia adds to the carbon atom and water is lost, producing an imine, a compound with a nitrogen atom double-bonded to a carbon atom.

Other ammonia derivatives include hydroxylamine (H₂NOH), hydrazine (H₂NNH₂) and semicarbazide (H₂NNHCONH₂).

The aldol condensation involves an aldehyde acting as both an electrophile (keto form) and nucleophile (enol or enolate form).  The product contains both alcohol and aldehyde functional groups.

With a stronger base and higher temperature, the water molecule is removed and a double bond forms through aldol condensation.

The Wittig reaction forms carbon-carbon double bonds by converting the C=O bond in aldehydes and ketones into C=C bonds in alkenes.

A phosphonium salt is formed from the SN2 reaction of an alkyl halide with the nucleophile triphenylphosphine (C₆H₅)₃P.

The phosphonium salt is then deprotonated with a strong base, yielding a ylide or phosphorane.  (The ylide form is a zwitterion, a molecule with both positive and negative charges).

When combined with an aldehyde or ketone, the ylide attacks the carbonyl carbon to yield a alkene and triphenylphosphineoxide.

Any oxidizing agent (except PCC) can oxidize aldehydes into carboxylic acids.

Common mild reagents to reduce aldehydes and ketones to alcohols are lithium alumnium hydride (LAH) and sodium borohydride (NaBH₄).

In the Wolff-Kishner reduction, the carbonyl is converted to a hydrazone (=NNH₂), which then releases molecular nitrogen (NH₂) when heated with a base to form a stable alkane.

Alcohols have the general formula ROH. The functional group is -OH, referred to as a hydroxyl group.

Alcohols are named by replacing the -e ending of the root alkane with the ending -ol.  The carbon atom attached to the hydroxyl group must be included in the longest chain and receives the lowest possible number.

Alternatively, the alkyl group can be named as a derivative, followed by the word alcohol.

Alcohols can be attached to aromatic rings.  These compounds are called phenols and have the general formula ArOH.

The boiling points of alcohols are significantly higher due to intermolecular hydrogen bonding (which also increases solubility in water).

Molecules with more than one hydroxyl group show greater degrees of hydrogen bonding and higher boiling points.

The hydroxyl hydrogen atom is weakly acidic, and alcohols can dissociate into protons and alkoxy ions.

Hydroxyl hydrogens of phenols are more acidic than those of alcohols.  The aromatic nature of the ring allows for distribution of negative charge throughout the ring, stabilizing the anion.

Electron-withdrawing substituents increase acidity, and electron-donating groups decrease acidity.

For aliphatic alcohols, the more alkyl groups that are present, the less acidic the molecule is (opposite of the trend for carbocations).

Because alkyl groups donate electron density, they help stabilize a positive charge but will destabilize a negative charge. (!!!)

The key mechanisms for alcohols and ethers are:

Nucleophilic substitutions: SN1, SN2

Electrophilic addition to a double bond

Nucleophilic addition to a carbonyl

(Review addition of water to double bonds. Review SN1 and SN2 reactions to produce alcohol.)

Alcohols can be prepared from the reduction of aldehydes, ketones, carboxylic acids or esters.  Lithium aluminum hydride (LAH) and sodium borohydride (NaBr₄) are the two most common reducing agents.

LAH reduces almost anything all the way to an alcohol. NaBH₄ is weaker, so while it will reduce aldehydes, ketones or acyl chlorides, it cannot reduce esters, carboxylic acids or amides.

Phenols can be synthesized from arylsulfonic acids with hot NaOH.  However, most functional groups are destroyed by the harsh reaction conditions.

A more versatile method of synthesizing phenols is by hydrolyzing diazonium salts.

Alcohols can be dehydrated in a strongly acidic solution (usually H₂SO₄) to produce alkenes.  Acidic solution is needed to protonate the -OH group and convert it to a good leaving group.

The mechanism is E1 for secondary and tertiary alcohols but E2 for primary alcohols.

(The more stable alkene is the major product, through the movement of a proton to produce the more stable 2° carbocation known as hydride shift.)

POCl₃ (phosphorus oxychloride) can also follow a E2 mechanism for primary and secondary alcohols by converting the -OH group into a good leaving group.

The displacement of hydroxyl groups in substitution reactions is rate because the hydroxide ion is a poor leaving group.  However, it can be converted to water (good leaving group for SN1) or a tosylate group (excellent leaving group for SN2).

The conversion of alcohols to alkyl halides involves the formation of inorganic esters, which readily undergo SN2 reactions.

Alcohols react with thionyl chloride to produce an intermediate, which is attacked by a chloride ion to form the alkyl chloride with inversion of configuration.

When alcohol is treated with PBr₃, it produces alkyl bromides.

The oxidation of alcohols generally involves some form of chromium (VI) as the oxidizing agent, which is reduced to chromium (III).

All oxidizing agents on the MCAT will convert a primary alcohol into a carboxylic acid except for PCC (pyridinium chlorochromate).  PCC only partially oxidizes primary alcohols to aldehydes because it lacks the water to hydrate aldehydes to diols.

Alkali dichromate salts (Na₂Cr₂O₇ or K₂Cr₂O₇) fully oxidize primary and secondary alcohols to carboxylic acids and ketones.

Cromium trioxide (CrO₃) is often dissolved with dilute sulfuric acid in acetone in a reaction called Jone's oxidation to oxidize primary and secondary alcohols to carboxylic acids and ketones.

Treatment of phenols with oxidizing reagents produce compounds called quinones (2,5-cyclohexadiene-1,4-diones).

An ether is a compound with two alkyl (or aryl) groups bonded to an oxygen atom.  Ethers are aprotic and unreactive.

Ethers are named as alkoxyalkanes, with the smaller chain as the prefix and the larger chain as the suffix.

Exceptions for these rules occur for cyclic ethers:

Esters boil at approximately the same temperatures of alkanes of comparable molecular weight.  Esters are only slightly polar and, therefore, only slightly soluble in water.

The Williamson ether synthesis produces ethers from the reaction of metal alkoxides with primary alkyl halides or tosylates.  Alkoxides behave as nucleophiles and displace the halide or tosylate via an SN2 reaction.

(Alkoxides only attack nonhindered halides.)

The Williamson ether synthesis can also be applied to phenols.

Cyclic ethers can be prepared through internal SN2 displacement.

Cyclic ethers can also be produced through oxidation of an alkene with a peroxy acid such as mcpba, yielding an epoxide or oxirane.

Esters react with oxygen in air to form highly explosive compounds called peroxides (general formula ROOR).

Cleavage of straight-chain ethers take place only under vigorous conditions, usually at high temperatures in the presence of HBr or HI.

Cleavage is initiated by protonation of the oxygen, which then proceeds by an SN1 or SN2 mechanism. 

Because epoxides are highly strained cyclic ethers, they are ready to react and susceptiple to SN2 reactions.

Aromatic describes any usually stable ring structure.  Aromatic compounds are cyclic, conjugated polyenes that posses 4n + 2 π electrons and adopt planar conformations to allow maximum overlap of their conjugated π orbitals.

A system is conjugated if it contains atoms connected by alternating single and multiple (double or triple) bonds.

Hückel's rule states a cyclic conjugated polyene with 4n + 2 π electrons is an aromatic compound, with extra stability resulting from filled bonding orbitals.

Any compound that is not aromatic is aliphatic.

If a compound fits all the characteristics of an aromatic compound except for Hückel's rule (if it has only 4n π electrons), it is antiaromatic and destabilized.

Aromatic compounds are aryl compounds, or arenes, and can be represented by Ar. 

When named as constituents, benzene is represented by Ph. Benzyl is the PhCH₂- group.

Aliphatic compounds are alkyls and represented by R.

A 1,2-disubstituted compound is called ortho-, or o-.  A 1,3-disubstituded compound is called meta-, or m-. A 1,4-disubstituted compounded is called para-, or p-.

Pyridine and pyrrole both have lone pairs on their nitrogen atoms, which tend to function as bases.

Pyrridine's lone pair can function as a base because it already has the six necessary π electrons in its ring, while pyrrole's cannot because its lone pairs are participating in the aromaticity of the molecule.

Delocalized electrons fin aromatic compounds form two π electron clouds, one above and one below the plane of the ring.  This delocalization stabilizes the molecule, making it fairly unreactive.

Some aromatic compounds do not undergo addition reactions as they prefer to maintain their aromaticity.

Aromatic compounds will undergo electrophilic aromatic substitution (EAS) reactions, as the end product restores aromaticity.

Halogenation: Aromatic rings react with bromine or chlorine in the presence of a Lewis acid (such as FeCl₃, FeBr₃, AlBr₃ or AlCl₃) to produce a good yield of monosubstituted products.

Fluorine, which is highly reactive, tends to produce multisubstituted products.

Iodine's lack of reactivity requires special conditions for the reaction to proceed.

Sulfonation: The aromatic ring reacts with fuming sulfuric acid to form sulfonic acid. Reversible.

Nitration: A mixture of nitric and sulfuric acids is used to create a nitronium ion (NO₂⁺), a strong electrophile. Nitronium reacts with aromatic rings to produce nitro compounds.

The product of this reaction is the least reactive substituted aromatic compound,

Acylation (Friedel-Crafts Reactions): An acyl group is turned into a carbocation, a strong electrophile, by a Lewis acid catalyst such as AlCl₃.  The carbocation acyl group is incorporated into an aromatic ring.

Substituents on an aromatic ring can be grouped on whether they enhance substitution (activating) or inhibit substitution (deactivation).  The groups that donate electron density are called activators, and groups that withdraw electron density are called deactivators.

If an activator is attached, new substituents are directed to the ortho or para position.  If a deactivator is attached, second substitutions, although less likely, will occur only at the meta position.

Halogens are the only deactivators that direct to the ortho or para position.

Benzene rings can be reduced to cyclohexane by catalytic hydrogenation, although this only occurs under vigorous conditions (high temperature and pressure).

Ruthenium or rhodium on carbon are the most common catalysts.

Step 1: Read and Annotate

Step 2: Prewrite First Task (not necessarily task 1)

Step 3: Prewrite Second Task

Step 4: Prewrite Third Task

Step 5: Clarify Main Idea and Plan

Step 6: Write

Step 7: Proofread

Task I: Explain what the statement means to you. Describe an example. Use an effective hook.

Task II: Describe a specific counter-example. Explain the relevance of your counter-example. Use regular transitions.

Task III: Discuss the criteria for tasks I and II. Resolve the apparent contradiction. End with a bang.

The Law of Conservation of Matter states that matter can neither be created nor destroyed.

Combination reactions involve two or more reactants which combine to form one product.

A + B → AB

The combustion reaction is a type of combustion reaction, where the substance is burned in the process of a gas.

Formation reactions are a type of combination reaction in which a single product is formed from elements in their standard states.

Metals deteriorate in corrosion reactions when a liquid or gas (usually oxygen) chemically attacks the surface of the metal.

Decomposition reactions occur when a compound breaks down into two or more substances, usually as a result of heating, electrolysis or light.

AB → A + B

Single displacement reactions occur when an atom (or ion) of one compound is replaced by an atom of another element.

A + BC → AB + C

In a redox reaction, electrons are transferred between species.  The oxidation of at least one element will change.

The oxidation number is the number assigned to an atom in an ion or molecule that denotes its real or hypothetical charge.

Oxidation is the loss of electrons by a species; reduction is a gain of electrons.

An oxidizing agent is a substance that accepts electrons from another species.  A reducing agent is a substance that donates electrons to another species.

In double displacement reactions, also called metathesis reactions, elements from two different compounds displace each other to form two new compounds.

AB + CD → AC + BD

Neutralization reactions involve an acid and a abase reacting to form a salt and usually water.

A solution consists of a solute dissolve in a solvent. The solvent is the component of the solution whose phase remains the same after mixing. If both substances are the same phase, the solvent is the component present in greater quantity. If both same-phase components are equal proportions, the component considered the solvent is the one more commonly identified as a solvent.

Solvation, or dissolution, is the electrostatic interaction between solute and solvent molecules.  Solvation when water is the solvent is hydration, and the resulting solution is aqueous.

Solvation involves breaking intermolecular interactions between solute molecules and between solvent molecules, while forming new intermolecular interactions between solute and solvent molecules.

When new interactions are stronger, solvation is exothermic and favored at low temperatures.

Dissolution of gases into liquids is exothermic because the only significant interactions that must be broken are those between water molecules.

When new interactions are weaker, solvation is endothermic and the process is favored at high temperatures.  Most dissolutions are this type.

The solubility of a substance is the maximum amount of that substance that can be dissolved in a particular solvent at a particular temperature.

When the maximum amount of solute is added, the dissolved solute is in equilibrium with its undissolved state and the solution is saturated.

If more solute is added to an already saturated solution, it will remain in solid form, precipitating to the bottom of the container.

Solute that dissolve minimally in the solvent are called sparingly soluble salts.

There are seven general solubility rules for aqueous solutions, which are solutions in which the solvent is water:

All salts of alkali metals are water soluble.

All salts of the ammonium ion (NH₄⁺) are water soluble.

All chlorides, bromides and iodides are water soluble, with the exceptions of Ag⁺, Pb²⁺ and Hg₂²⁺.

All salts of the sulfate ion (SO₄²⁻) are water soluble, with the exceptions of Ca²⁺, Sr²⁺, Ba²⁺ and Pb²⁺.

All metal oxides are insoluble, with the exception of the alkali metals and CaO, SrO and BaO, all of which hydrolyze to form solutions of the corresponding metal hydroxides.

All hydroxides are insoluble, with the exception of the alkali metals and Ca²⁺, Sr²⁺ and Ba²⁺.

All carbonates (CO₃²⁻), phosphates (PO₄³⁻), sulfides (S²⁻) and sulfites (SO₃²⁻) are insoluble, with the exception of the alkali metals and ammonium.

All sodium salts and nitrate salts are completely soluble.

Ionic compounds are held together by the ionic bond, which is the force of electrostatic attraction between cations and anions.

The nomenclature for ionic compounds is based on the names of the component ions:

For elements that can form more than one cation, the charge is indicated by Roman numerals in parentheses following the name (e.g., Iron (II)).

The endings -ous or -ic are added to the root of the Latin name of the element to represent ions with lesser or greater charge, respectively (e.g., ferrous).

Monatomic anions are named by replacing the ending of the name of the element with -ide (e.g., hydride).

Polyatomic anions containing oxygen are called oxyanions.  When an element forms two oxyanions, the name of the one with less oxygen ends in -ite and the other with -ate (e.g., nitrite).

When the series of oxyanions contains four oxyanions, hypo- and per- are used to indicate less and more oxygen, respectively (e.g., hypochlorite).

Polyatomic anions often gain H⁺ ions to form anions of lower charge.  They are named by adding hydrogen or dihydrogen to the front of the anion's name, or with the prefix bi- to indicate the addition of a single hydrogen ion (e.g., hydrogen carbonate).

A solute is considered a strong electrolyte if it dissociates completely, while weak electrolytes ionize or hydrolyze incompletely in aqueous solution.

Percentage composition by mass (w/w%) of a solution is the mass of the solute divided by the mass of the solution, multiplied by 100 percent.

The mole fraction (X) of a compound is the number of moles of the compound divided by the total number of moles of all species within the system.

Molality (m) is the number of moles of solute per kilogram of solvent.

An ionic solid introduced into a polar equilibrium dissociates into its component ions: A_mB_n (s) ↔ mA^n+ (aq) + nB^m- (aq)

For a saturated solution of the ionic compound A_mB_n, the equilibrium constant for its solubility is called the solubility product constant: K_sp = [A^n+]^m [B^m-]^n

The solubility product constant increases with increasing temperature for not gas solutes and decreases for gas solutes.  Higher pressures favor dissolution of gas solutes.