With the formula C < sub > n </ sub > H < sub > 2n + 2 </ sub >, Alkanes belong to a homologous series of organic compounds in which the members differ by a constant relative molecular mass of 14.

The Arrhenius definition states that acids are substances which increase the concentration of hydronium ions ( H < sub > 3 </ sub > O < sup >+</ sup >) in solution.

An Arrhenius acid is a substance that increases the concentration of the hydronium ion, H < sub > 3 </ sub > O < sup >+</ sup >, when dissolved in water.

In pure water the majority of molecules exist as H < sub > 2 </ sub > O, but a small number of molecules are constantly dissociating and re-associating.

Note that chemists often write H < sup >+</ sup >( aq ) and refer to the hydrogen ion when describing acid-base reactions but the free hydrogen nucleus, a proton, does not exist alone in water, it exists as the hydronium ion, H < sub > 3 </ sub > O < sup >+</ sup >.

Brackets indicate concentration, such that means the concentration of H < sub > 2 </ sub > O.

Of those, ethanol ( C < sub > 2 </ sub > H < sub > 5 </ sub > OH ) is the type of alcohol found in alcoholic beverages, and in common speech the word alcohol refers specifically to ethanol.

At the 2 November 2004 election Eni F. H. Faleomavaega of the Democratic Party ( United States ) defeated the Republican candidate and was re-elected.

According to Steven H Silver, alternate history requires three things: 1 ) the story must have a point of divergence from the history of our world prior to the time at which the author is writing, 2 ) a change that would alter history as it is known, and 3 ) an examination of the ramifications of that change.

They are known as 2 -, alpha -, or α-amino acids ( generic formula H < sub > 2 </ sub > NCHRCOOH in most cases < ref > Proline is an exception to this general formula.

Carboxylic acid groups (− CO < sub > 2 </ sub > H ) can be deprotonated to become negative carboxylates (− CO < sub > 2 </ sub >< sup >−</ sup > ), and α-amino groups ( NH < sub > 2 </ sub >−) can be protonated to become positive α-ammonium groups (< sup >+</ sup > NH < sub > 3 </ sub >−).

An amide is a compound with the functional group R < sub > n </ sub > E ( O )< sub > x </ sub > NR '< sub > 2 </ sub > ( R and R ' refer to H or organic groups ).

Amide can also refer to the conjugate base of ammonia ( the anion H < sub > 2 </ sub > N < sup >–</ sup >) or of an organic amine ( an anion R < sub > 2 </ sub > N < sup >–</ sup >).

The positively charged hydrogen ions ( protons ) capture electrons from the copper, forming bubbles of hydrogen gas, H < sub > 2 </ sub >.

: 2H < sup >+</ sup > + 2e < sup >−</ sup > < big >< big >→</ big ></ big > H < sub > 2 </ sub >

* H < sub > 2 </ sub > antagonists

The simplest alkene is ethylene ( C < sub > 2 </ sub > H < sub > 4 </ sub >), which has the International Union of Pure and Applied Chemistry ( IUPAC ) name ethene.

: CH < sub > 2 </ sub >= CH < sub > 2 </ sub > + H < sub > 2 </ sub > → CH < sub > 3 </ sub >- CH < sub > 3 </ sub >

Both theories easily describe the first reaction: CH < sub > 3 </ sub > COOH acts as an Arrhenius acid because it acts as a source of H < sub > 3 </ sub > O < sup >+</ sup > when dissolved in water, and it acts as a Brønsted acid by donating a proton to water.

# H < sub > 3 </ sub > O < sup >+</ sup >( aq ) + Cl < sup >−</ sup >( aq ) + NH < sub > 3 </ sub > → Cl < sup >−</ sup >( aq ) + NH < sub > 4 </ sub >< sup >+</ sup >( aq )

The species that gains the electron pair is the Lewis acid ; for example, the oxygen atom in H < sub > 3 </ sub > O < sup >+</ sup > gains a pair of electrons when one of the H — O bonds is broken and the electrons shared in the bond become localized on oxygen.

The numerical value of K < sub > a </ sub > is equal to the concentration of the products divided by the concentration of the reactants, where the reactant is the acid ( HA ) and the products are the conjugate base and H < sup >+</ sup >.

: CH < sub > 2 </ sub >= CH < sub > 2 </ sub > + X < sub > 2 </ sub > + H < sub > 2 </ sub > O </ sub > → XCH < sub > 2 </ sub >- CH < sub > 2 </ sub > OH

: R < sub > 1 </ sub >- CH = CH-R < sub > 2 </ sub > + O < sub > 3 </ sub > → R < sub > 1 </ sub >- CHO + R < sub > 2 </ sub >- CHO + H < sub > 2 </ sub > O

: SO < sub > 3 </ sub > ( g ) + H < sub > 2 </ sub > O ( l ) → H < sub > 2 </ sub > SO < sub > 4 </ sub > ( l )

: CaCO < sub > 3 </ sub > ( s ) + H < sub > 2 </ sub > SO < sub > 4 </ sub > ( aq ) CaSO < sub > 4 </ sub > ( aq ) + CO < sub > 2 </ sub > ( g ) + H < sub > 2 </ sub > O ( l )

H < sub > 2 </ sub > CO < sub > 3 </ sub >( aq ) CO < sub > 2 </ sub >( aq ) + H < sub > 2 </ sub > O ( l )

** H < sub > 2 </ sub > O ( l ) + 240kJ → H < sub > 2 </ sub > O ( g )

: 2 Dy ( s ) + 6 H < sub > 2 </ sub > O ( l ) → 2 Dy ( OH )< sub > 3 </ sub > ( aq ) + 3 H < sub > 2 </ sub > ( g )

: 2 Er ( s ) + 6 H < sub > 2 </ sub > O ( l ) → 2 Er ( OH )< sub > 3 </ sub > ( aq ) + 3 H < sub > 2 </ sub > ( g )

: Oxidation: 4 H < sub > 2 </ sub > O ( l ) + Mn < sup > 2 +</ sup >( aq ) → MnO < sub > 4 </ sub >< sup >–</ sup >( aq ) + 8 H < sup >+</ sup >( aq ) + 5 e < sup >–</ sup >

: Reduction: 2 e < sup >–</ sup > + 6 H < sup >+</ sup >( aq ) + BiO < sub > 3 </ sub >< sup >–</ sup >( s ) → Bi < sup > 3 +</ sup >( aq ) + 3 H < sub > 2 </ sub > O ( l )

: 8 H < sub > 2 </ sub > O ( l ) + 2 Mn < sup > 2 +</ sup >( aq ) → 2 MnO < sub > 4 </ sub >< sup >–</ sup >( aq ) + 16 H < sup >+</ sup >( aq ) + 10 e < sup >–</ sup >

Reactions of acids are often generalized in the form HA H < sup >+</ sup > + A < sup >−</ sup >, where HA represents the acid and A < sup >−</ sup > is the conjugate base.

Note that the acid can be the charged species and the conjugate base can be neutral in which case the generalized reaction scheme could be written as HA < sup >+</ sup > H < sup >+</ sup > + A.

An important class of alcohols are the simple acyclic alcohols, the general formula for which is C < sub > n </ sub > H < sub > 2n + 1 </ sub > OH.

: CH < sub > 3 </ sub >- CH = CH < sub > 2 </ sub > + HBr → CH < sub > 3 </ sub >- CHBr-CH < sub > 2 </ sub >- H

: CH < sub > 2 </ sub >= CH < sub > 2 </ sub > + H < sub > 2 </ sub > O </ sub > → CH < sub > 3 </ sub >- CH < sub > 2 </ sub > OH

: 2 CH < sub > 4 </ sub > → HC ≡ CH + 3 H < sub > 2 </ sub >

: RC ≡ CR ' + H < sub > 2 </ sub > → cis-RCH = CR ' H

: H < sub > 2 </ sub > C = C = CH < sub > 2 </ sub > CH < sub > 3 </ sub > C ≡ CH

: PhC ≡ CH + H < sub > 2 </ sub > O → PhCOCH < sub > 3 </ sub >

: HC ≡ CC < sub > 6 </ sub > H < sub > 12 </ sub > C ≡ CH + 2H < sub > 2 </ sub > O → CH < sub > 3 </ sub > COC < sub > 6 </ sub > H < sub > 12 </ sub > COCH < sub > 3 </ sub >