What is a Gran plot in chemistry?
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What is a Gran plot in chemistry?
A Gran plot (also known as Gran titration or the Gran method) is a common means of standardizing a titrate or titrant by estimating the equivalence volume or end point in a strong acid-strong base titration or in a potentiometric titration.
Why is Gran plot more accurate?
The value of the Gran plot is that data taken before the equivalence point can be used. These pH measurements tend to be more reliable than values obtained right around the equivalence point where the pH is rapidly changing.
Why is a Gran plot useful?
Gran plots are commonly used to find equivalence points in acid-base and oxidation-reduction potentiometric titrations. It is shown that a standard error estimate for the equivalence points in a Gran plot can be calculated from the titration data by a weighted nonlinear optimization method.
Is pH the same as pKa?
Difference Between pKa and pH pKa is the negative value of the logarithm of Ka. pH is the logarithmic value of the inverse of H+ concentration. pKa indicates whether an acid is a strong acid or a weak acid. pH indicates whether a system is acidic or alkaline.
How do you make a Scatter gram?
Scatter Diagram Procedure
- Collect pairs of data where a relationship is suspected.
- Draw a graph with the independent variable on the horizontal axis and the dependent variable on the vertical axis.
- Look at the pattern of points to see if a relationship is obvious.
- Divide points on the graph into four quadrants.
What is the point of a Gran plot?
What is Gran alkalinity?
Gran alkalinity method is a more accurate technique used explicitly for low level alkalinity samples. It is performed on samples with a pH less than 7.0. Method Summary. The alkalinity titration is carried well past the total inflection point to about pH 3.0.
Why salt bridge is used in potentiometric titration?
A salt bridge is used to prevent interference of the analyte with the reference electrode. The electric potential of the cell is dependent on the concentration of ions in contact with the indicator electrode, as shown in the above graph. As a result, the Ecell is measured after each titrant addition.
What is pI vs pH?
The isoelectric point (pI) is the pH of a solution at which the net charge of a protein becomes zero. At solution pH that is above the pI, the surface of the protein is predominantly negatively charged, and therefore like-charged molecules will exhibit repulsive forces.
What is pKb?
pKb is the criterion used to estimate the alkalinity of the molecule. It is used to measure basic strength. The lesser the pKb is, the more potent the base will be. It is equivalent to the negative logarithm of base dissociation constant, Kb. pKb = – log Kb.
What are the 4 characteristics of a scatter plot?
Form: Is the association linear or nonlinear? Direction: Is the association positive or negative? Strength: Does the association appear to be strong, moderately strong, or weak? Outliers: Do there appear to be any data points that are unusually far away from the general pattern?
