Help


[permalink] [id link]
+
Page "Acid–base reaction" ¶ 4
from Wikipedia
Edit
Promote Demote Fragment Fix

Some Related Sentences

Arrhenius and definition
There are three common definitions for acids: the Arrhenius definition, the Brønsted-Lowry definition, and the Lewis definition.
The Arrhenius definition states that acids are substances which increase the concentration of hydronium ions ( H < sub > 3 </ sub > O < sup >+</ sup >) in solution.
In the second example CH < sub > 3 </ sub > COOH undergoes the same transformation, in this case donating a proton to ammonia ( NH < sub > 3 </ sub >), but cannot be described using the Arrhenius definition of an acid because the reaction does not produce hydronium.
This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base and are still among the more common bases.
Liebig's definition, while completely empirical, remained in use for almost 50 years until the adoption of the Arrhenius definition.
More recent IUPAC recommendations now suggest the newer term " hydronium " be used in favor of the older accepted term " oxonium " to illustrate reaction mechanisms such as those defined in the Brønsted Lowry and solvent system definitions more clearly, with the Arrhenius definition serving as a simple general outline of acid base character.
The Arrhenius definition can be summarised as " Arrhenius acids form hydrogen ions in aqueous solution with Arrhenius bases forming hydroxide ions.
The universal aqueous acid base definition of the Arrhenius concept is described as the formation of water from a proton and hydroxide ions, or hydrogen ions and hydroxide ions from the dissociation of an acid and base in aqueous solution:
* Arrhenius definition: Acids dissociate in water releasing H < sub > 3 </ sub > O < sup >+</ sup > ions ; bases dissociate in water releasing OH < sup >–</ sup > ions.
* Brønsted-Lowry definition: Acids are proton ( H < sup >+</ sup >) donors, bases are proton acceptors ; this includes the Arrhenius definition.
# REDIRECT Acid base reaction # Arrhenius definition

Arrhenius and acid
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.
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.
As defined by Arrhenius, acid base reactions are characterized by Arrhenius acids, which dissociate in aqueous solution to form hydrogen ions (), and Arrhenius bases, which form hydroxide () ions.
The simplest is Arrhenius theory, which states than an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water.
The liberated proton combines with a water molecule to give a hydronium ( or oxonium ) ion H < sub > 3 </ sub > O < sup >+</ sup >, and so Arrhenius later proposed that the dissociation should be written as an acid base reaction:
Neutralizations with Arrhenius acids and bases always produce water where acid alkali reactions produce water and a metal salt.

Arrhenius and
* 1859 Svante Arrhenius, Swedish chemist, Nobel laureate ( d. 1927 )
* Chemistry Svante August Arrhenius
* February 19 Svante Arrhenius, Swedish chemist, Nobel Prize laureate ( d. 1927 )
* October 2 Svante Arrhenius, Swedish chemist, Nobel Prize laureate ( b. 1859 )
Since the frequency range of the typical noise experiment ( e. g. 1 Hz 1 kHz ) is low compared with typical microscopic " attempt frequencies " ( e. g. 10 < sup > 14 </ sup > Hz ), the exponential factors in the Arrhenius equation for the rates are large.
* 1889 Svante Arrhenius introduces the idea of activation energy for chemical reactions, giving the Arrhenius equation.
* Arrhenius equation Svante August Arrhenius
* Carl Axel Arrhenius ( 1757 1824 ), Swedish chemist and discoverer of the element yttrium
* Svante Arrhenius ( 1859 1927 ), Swedish physical chemist and 1903 Nobel laureate

Arrhenius and base
An Arrhenius base is a molecule which increases the concentration of the hydroxide ion when dissolved in water.
The second subset of base is also called an Arrhenius base.
; it is indeed the strongest Arrhenius base, but a number of compounds that cannot exist in aqueous solution, such as n-butyllithium and sodium amide, are more basic.

Arrhenius and reactions
While the Arrhenius concept is useful for describing many reactions, it is also quite limited in its scope.
A historically useful generalization supported by the Arrhenius equation is that, for many common chemical reactions at room temperature, the reaction rate doubles for every 10 degree Celsius increase in temperature.
In short, the Arrhenius equation gives " the dependence of the rate constant k of chemical reactions on the temperature T ( in absolute temperature kelvins ) and activation energy E < sub > a </ sub >", as shown below:
Reactions without an activation barrier ( e. g., some radical reactions ), tend to have anti Arrhenius temperature dependence: the rate constant decreases with increasing temperature.
Swedish chemist Svante Arrhenius studied this phenomenon during the late 1880s, and stated the relations between reactive molecular encounters and rates of reactions ( formulated in terms of activation energies ).
In addition, the rates at four temperatures were measured for seven of the dienes permitting calculations of the enthalpy of activation ( ΔH < sup >‡</ sup >) and entropy of activation ( ΔS < sup >‡</ sup >) for these reactions through the Arrhenius equation.

Arrhenius and is
CRESU experiments have been used to show deviations from Arrhenius kinetics at low temperatures: as the temperature is reduced, the rate constant actually increases.
In chemistry, activation energy is a term introduced in 1889 by the Swedish scientist Svante Arrhenius that is defined as the energy that must be overcome in order for a chemical reaction to occur.
At a more advanced level, the Arrhenius Activation energy term from the Arrhenius equation is best regarded as an experimentally determined parameter that indicates the sensitivity of the reaction rate to temperature.
While this equation suggests that the activation energy is dependent on temperature, in regimes in which the Arrhenius equation is valid this is cancelled by the temperature dependence of k. Thus, E < sub > a </ sub > can be evaluated from the reaction rate coefficient at any temperature ( within the validity of the Arrhenius equation ).

Arrhenius and hydrogen
The Swedish chemist Svante Arrhenius attributed the properties of acidity to hydrogen in 1884.
Hence a pH indicator is a chemical detector for hydronium ions ( H < sub > 3 </ sub > O < sup >+</ sup >) or hydrogen ions ( H < sup >+</ sup >) in the Arrhenius model.

0.112 seconds.