Examples of dissociation curve in the following topics:
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- The lower areas of the curve show saturation when oxygen is unloaded into the tissues.
- The oxyhemoglobin dissociation curve can shift in response to a variety of factors.
- A change in the P50 of the curve is a sign that the dissociation curve as a whole has shifted.
- The oxygen–hemoglobin dissociation curve plots the percent hemoglobin saturation (y-axis) against the partial pressure of oxygen in the blood (PO2).
- The blue curve is standard curve, while the red and green curves are right and leftward shifts respectively.
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- The resulting graph, an oxygen dissociation curve, is sigmoidal, or S-shaped .
- The oxygen dissociates from the Hb molecule, shifting the oxygen dissociation curve to the right.
- A similar shift in the curve also results from an increase in body temperature.
- The oxygen dissociation curve demonstrates that as the partial pressure of oxygen increases, more oxygen binds hemoglobin.
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- As a result, the oxygen-binding curve of hemoglobin (also called the oxygen saturation or dissociation curve) is sigmoidal, or S-shaped, as opposed to the normal hyperbolic curve associated with noncooperative binding.
- This curve shows the saturation of oxygen bound to hemoglobin compared to the partial pressure of oxygen (concentration) in blood.
- That's because most carbon dioxide travels through the blood as a bicarbonate ion, which is the dissociated form of carbonic acid in solution.
- This dissociates in solution into bicarbonate and hydrogen ions, the driving force of pH in the blood.
- A reduction in the total binding capacity of hemoglobin to oxygen (i.e. shifting the curve down, not just to the right) due to reduced pH is called the Haldane effect.
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- Diprotic and polyprotic acids show unique profiles in titration experiments, where a pH versus titrant volume curve clearly shows two equivalence points for the acid; this is because the two ionizing hydrogens do not dissociate from the acid at the same time.
- Dissociation does not happen all at once; each dissociation step has its own Ka value, designated Ka1 and Ka2:
- This first dissociation step of sulfuric acid will occur completely, which is why sulfuric acid is considered a strong acid; the second dissociation step is only weakly dissociating, however.
- A triprotic acid (H3A) can undergo three dissociations and will therefore have three dissociation constants: Ka1 > Ka2 > Ka3.
- The titration curve of a polyprotic acid has multiple equivalence points, one for each proton.
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- Monoprotic acids are acids able to donate one proton per molecule during the process of dissociation (sometimes called ionization) as shown below (symbolized by HA):
- If the pH of this titration were recorded and plotted against the volume of NaOH added, a very clear picture of the stepwise neutralization emerges, with very distinct equivalence points on the titration curves.
- Oxalic acid is an example of an acid able to enter into a reaction with two available protons, having different Ka values for the dissociation (ionization) of each proton.
- This image shows how Oxalic Acid will lose two protons in successive dissociations.
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- The major characteristic of all dissociative phenomena involves a detachment from reality.
- Although some dissociative experiences involve memory loss, others do not.
- At the pathological end of the dissociation spectrum are the dissociative disorders.
- Psychoactive drugs can often induce a state of temporary dissociation.
- Pathological dissociation involves the dissociative disorders, including dissociative fugue and depersonalization disorder.
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- To determine percent dissociation, we first need to solve for the concentration of H+.
- However, because the acid dissociates only to a very slight extent, we can assume x is small.
- As we would expect for a weak acid, the percent dissociation is quite small.
- However, for some weak acids, the percent dissociation can be higher—upwards of 10% or more.
- Calculate percent dissociation for weak acids from their Ka values and a given concentration.
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- The acid dissociation constant (Ka) is the measure of the strength of an acid in solution.
- Acid dissociation constants are most often associated with weak acids, or acids that do not completely dissociate in solution.
- The larger the value of pKa, the smaller the extent of dissociation.
- Acetic acid is a weak acid with an acid dissociation constant $K_a=1.8\times 10^{-5}$ .
- The acetic acid partially and reversibly dissociates into acetate and hydrogen ions.
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- More pathological dissociation involves dissociative disorders.
- These are both examples of dissociation.
- Dissociation of this sort is fairly normal from time to time; however, there are five types of dissociative disorders which are considered psychopathological: dissociative identity disorder, disociative amnesia, depersonalization/derealization disorder, other specified dissociative disorder, and unspecified dissociative disorder.
- Dissociative fugue, while it used to be its own diagnosis in the previous DSM-IV-TR, is now subsumed under dissociative amnesia as a specifier (i.e., dissociative amnesia with or without dissociative fugue).
- The old category of dissociative disorder not otherwise specified is now split into two according to the DSM-5 (2013): other specified dissociative disorder and unspecified dissociative disorder.
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- These energy values (493 and 424 kJ/mol) required to break successive O-H bonds in the water molecule are called 'bond dissociation energies,' and they are different from the bond energy.
- The bond energy is the average of the bond dissociation energies in a molecule.
- A Morse curve shows how the energy of a two atom system changes as a function of internuclear distance.
- The attractive and repulsive forces are balanced at the minimum point in the plot of a Morse curve.
- A Morse curve will have different energy minima and distance dependence for bonds formed between different pairs of atoms.