Hence, the difference in Pauling electronegativity between hydrogen and bromine is 0. 73 ( dissociation energies: H – Br, 3. 79 eV ; H – H, 4. 52 eV ; Br – Br 2. 00 eV )

The H – H bond is one of the strongest bonds in chemistry, with a bond dissociation enthalpy of 435. 88 kJ / mol at 298 K. As a consequence of this strong bond, H < sub > 2 </ sub > dissociates to only a minor extent until higher temperatures.

: H < sub > 2 </ sub > SO < sub > 4 </ sub > + 2 H < sub > 2 </ sub > O → SO < sub > 4 </ sub >< sup > 2 –</ sup > + 2 H < sub > 3 </ sub > O < sup >+</ sup > ( sulfuric acid dissociation )

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:

In the case of hydrogen, adsorption is most often accompanied with dissociation of molecular hydrogen ( H < sub > 2 </ sub >) to atomic hydrogen ( H ), followed by spillover of the hydrogen atoms present.

One study, A. H. Crisp and colleagues, of St. George's Hospital Medical School in London, suggests higher levels of dissociation in adult sleepwalkers, since test subjects scored unusually high on the hysteria portion of the " Crown-Crisp Experiential Index ".

The excess β chains form unstable tetramers ( called Hemoglobin H or HbH of 4 beta chains ), which have abnormal oxygen dissociation curves.

Although the bond dissociation energy D for a carbon-carbon single bond is relatively high ( about 375 kJ / mol ) and cracking is highly endothermic, the large positive entropy change resulting from the fragmentation of one large molecule into several smaller pieces, together with the extremely high temperature, makes T ∆ S ° term larger than the ∆ H ° term, thereby favoring the cracking reaction.

* pK < sub > a H < sub > 2 </ sub > CO < sub > 3 </ sub ></ sub > is the cologarithm of the acid dissociation constant of carbonic acid.

Acidity results from the dissociation of the H < sup >+</ sup > ion at physiological pH of metabolic ketone bodies such as acetoacetate, and β-hydroxybutyrate.

It should be noted, however, that deuteration changes the heats of adsorption and the boiling and freezing points of molecules ( boiling points: 100. 0 ° C for H < sub > 2 </ sub > O vs. 101. 42 ° C for D < sub > 2 </ sub > O ; melting points: 0. 0 ° C for H < sub > 2 </ sub > O, 3. 82 ° C for D < sub > 2 </ sub > O ), pKa ( i. e., dissociation constant: 9. 71x10 < sup >- 15 </ sup > for H < sub > 2 </ sub > 0 vs. 1. 95x10 < sup >- 15 </ sup > for D < sub > 2 </ sub > O, cf.

The dissociation of acids in a solution means the split-off of a proton H < sup >+</ sup >, see Acid-base reaction theories.

It should be noted, however, that deuteration changes the heats of adsorption and the boiling and freezing points of molecules ( boiling points: 100. 0 ° C for H < sub > 2 </ sub > O vs. 101. 42 ° C for D < sub > 2 </ sub > O ; melting points: 0. 0 ° C for H < sub > 2 </ sub > O, 3. 82 ° C for D < sub > 2 </ sub > O ), p < i > K </ i >< sub > a </ sub > ( i. e., dissociation constant: 9. 71 × 10 < sup >- 15 </ sup > for H < sub > 2 </ sub > O vs. 1. 95 × 10 < sup >- 15 </ sup > for D < sub > 2 </ sub > O, cf.

A significant effect discovered during the study is the existence of Prandtl numbers reaching values of more than unity in the nitrogen dissociation region.

Another effect discovered is the large coefficient of thermal diffusion tending to separate nitrogen from the oxygen when temperature differences straddling the nitrogen dissociation region are present.

Argon was used as a blowing gas to exclude any effects of dissociation or chemical reaction.

It would appear that it should be possible to determine unique mechanisms for the thermal and photochemical reactions in both the liquid and gas phases and to determine values for activation energies of some of the intermediate reactions of atoms and free radicals, as well as information on the heat of dissociation of the carbon-halogen bond.

The acid dissociation constant K < sub > a </ sub > is generally used in the context of acid-base reactions.

Akt phosphorylates and inhibits Bas ( a Bcl-2 family member ), causing Bas to interact with the 14-3-3 scaffold, resulting in Bcl dissociation and thus cell survival.

In transition regions, where this pressure dependent dissociation is incomplete, both the differential, constant pressure heat capacity and beta ( the volume / pressure differential ratio ) will greatly increase.

Hypersonic flow is characterized by high temperature flow behind a shock wave, viscous interaction, and chemical dissociation of gas.

If mineral acid is added to the acetic acid mixture, increasing the concentration of hydronium ion, the amount of dissociation must decrease as the reaction is driven to the left in accordance with this principle.

Analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts.

With a time-lapse series of scanning tunneling microscopy images, they determined the molecules undergo adsorption, dissociation and diffusion before reacting.

With up to 13 adjustable parameters they obtained a result very close to the experimental result for the dissociation energy.

Only one molecule is involved in a unimolecular reaction ; it is transformed by an isomerization or a dissociation in one or more other molecules.

In a typical dissociation reaction, a bond in a molecule splits ( ruptures ) resulting in two molecular fragments.

The equilibrium is determined by the acid and base dissociation constants ( K < sub > a </ sub > and K < sub > b </ sub >) of the involved substances.

Other factors are probably involved, such as the association and dissociation of transcription factor complexes with chromatin.

In chemistry, biochemistry, and pharmacology, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate ( dissociate ) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions.

The dissociation constant is usually denoted and is the inverse of the association constant.

In the special case of salts, the dissociation constant can also be called an ionization constant.

One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encountered case where x = y = 1, K < sub > d </ sub > has a simple physical interpretation: when = K < sub > d </ sub >, = or equivalently /(+)= 1 / 2.

The dissociation constant is commonly used to describe the affinity between a ligand () ( such as a drug ) and a protein () i. e. how tightly a ligand binds to a particular protein.

Protein binding can be extraordinarily tight and specific ; for example, the ribonuclease inhibitor protein binds to human angiogenin with a sub-femtomolar dissociation constant (< 10 < sup >− 15 </ sup > M ) but does not bind at all to its amphibian homolog onconase (> 1 M ).

Electron-capture dissociation typically involves a multiply protonated molecule M interacting with a free electron to form an odd-electron ion

Wilhelm Ostwald ’ s dilution law is a relationship between the dissociation constant and the degree of dissociation of a weak electrolyte ( acids, bases ).

Lyme disease serology is indicated in patients with transverse myelitis keeping in mind that dissociation in Lyme antibody titers between the blood and the CSF is possible.

Efforts to psychometrically distinguish between normal and pathological dissociation have been made, but they have not been universally accepted.

The cause of DID is controversial, with debate occurring between supporters of different hypotheses: that DID is a reaction to the trauma ; that DID is produced iatrogenically by inappropriate psychotherapeutic techniques that cause a patient to enact the role of a patient DID ; and newer hypotheses involving memory processing that allows for the possibility that trauma-causing dissociation can occur after childhood in DID as it does in PTSD.

Plaque on the former house of Pierre Janet | Pierre Marie Félix Janet ( 1859-1947 ), the philosopher and psychologist who first drew a connection between events in the subject's past life and present mental health, also coining the words " dissociation " and " subconscious "

There are also profound changes in the sense of self: the ego may separate from the body ( dissociation ), or the boundary between self and environment may dissolve .</ p >

There is a dissociation between the process associated with the actual execution of the physical movements of the limb and the process that produces an internal sense of voluntary control over the movements, with this latter process thus normally creating the internal conscious sensation that the movements are being internally initiated, controlled and produced by an active self.

Invited Editorial: When aliens invade: multiple mechanisms for dissociation between will and action.

It is likely that the disconnect between having the knowledge and remembering the context in which the knowledge was acquired is due to a dissociation between semantic and episodic memory – an individual retains the semantic knowledge ( the fact ), but lacks the episodic knowledge to indicate the context in which the knowledge was gained.

Studies have shown that there is dissociation between provoked confabulation, spontaneous confabulation ( which is unprovoked ) and false memories.

* In the third mechanism, the Manzetti-mechanism, Manzetti Sergio and colleagues provided evidence that a coordination between water and zinc during catalysis was unlikely, and suggested a third mechanism wherein a histidine from the HExxHxxGxxH-motif participates in catalysis by allowing the Zn < sup > 2 +</ sup > ion to assume a quasi-penta coordinated state, via its dissociation from it.

The second acid dissociation constant, however, is the point halfway between the first equivalence point and the second equivalence point ( and so on for acids that release more than two protons, such as phosphoric acid ).

According to Gibbs free energy equation, the relation between dissociation equilibrium constant, K < sub > d </ sub >, and the components of free energy was built.

If the Bundle of His is blocked, it will result in dissociation between the activity of the atria and that of the ventricles, otherwise called a third degree heart block.

It is this dissociation that eventually breaks nearly all the bonds — literally, for Hushidh and Cheveya — between Nafai and his older brother, Elemak.

This suggested a relative dissociation of arousal between the two hemispheres in such people as compared with controls.

These findings indicate that there is a functional dissociation between the dorsal and ventral hippocampus.

Density functional methods have been applied to investigate the transimination reaction, and the results have shown that the reaction involves three sequential steps: ( i ) formation of a tetrahedral intermediate with the active site lysine and the amino substrate bonded to the PLP cofactor ; ( ii ) nondirect proton transfer between the amino substrate and the lysine residue ; and ( iii ) formation of the external aldimine after the dissociation of the lysine residue.

Upon binding to DNA ( the " Gyrase-DNA " state ), there is a competition between DNA wrapping and dissociation, where increasing DNA tension increases the probability of dissociation.