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A typical titration curve of a diprotic acid, oxalic acid, titrated with a strong base, sodium hydroxide.Both equivalence points are visible. Titrations are often recorded on graphs called titration curves, which generally contain the volume of the titrant as the independent variable and the pH of the solution as the dependent variable (because it changes depending on the composition of the ...
Inverted logistic S-curve to model the relation between wheat yield and soil salinity. Many natural processes, such as those of complex system learning curves, exhibit a progression from small beginnings that accelerates and approaches a climax over time. When a specific mathematical model is lacking, a sigmoid function is often used.
A calibration curve plot showing limit of detection (LOD), limit of quantification (LOQ), dynamic range, and limit of linearity (LOL).. In analytical chemistry, a calibration curve, also known as a standard curve, is a general method for determining the concentration of a substance in an unknown sample by comparing the unknown to a set of standard samples of known concentration. [1]
From the titration of protonatable group, one can read the so-called pK a 1 ⁄ 2 which is equal to the pH value where the group is half-protonated (i.e. when 50% such groups would be protonated). The pK a 1 ⁄ 2 is equal to the Henderson–Hasselbalch pK a (pK HH a) if the titration curve follows the Henderson–Hasselbalch equation. [14]
Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...
If the portions of the titration curve both prior to and after the endpoint are reasonably linear, then the intersection of tangents to these lines will accurately locate the endpoint. This is illustrated in Figure 2. Consider the reaction for the equation aA + bB = pP which is non-stoichiometric at equilibrium. Let A represent the titrant, and ...
In chemical thermodynamics, isothermal titration calorimetry (ITC) is a physical technique used to determine the thermodynamic parameters of interactions in solution. [ 1 ] [ 2 ] It is most often used to study the binding of small molecules (such as medicinal compounds) to larger macromolecules ( proteins , DNA etc.) in a label-free environment.
The analytical (total) concentration of a reactant R at the i th titration point is given by = + [] + where R 0 is the initial amount of R in the titration vessel, v 0 is the initial volume, [R] is the concentration of R in the burette and v i is the volume added. The burette concentration of a reactant not present in the burette is taken to be ...