How Do You Calculate The Buffer Capacity?

4 Answers

Danielle Joynson Profile
In order to calculate buffer capacity you will need to carry out a number of calculations, which can be quite challenging.

  • How to determine buffer capacity: Step 1
You should have a self-ionization solution of water along with a concentration figure of protons that reside in the solution. With these figures you will need to divide them by each other which should be written as follows: Kw/[H+]. This is not related to the buffer because it is a property of water.

  • Step 2
Once you have done that, you need to label the concentration of protons with 'A' and leave it separate to carry on with your calculations. You will now need to multiply the concentration of the acid you have by the dissociation of the acid in question. Then you should multiply that result by the concentration of protons. Once you have done that, you should set that figure aside and label it 'B'.

  • Step 3
Your next step is to multiply the dissociation of the acid by the concentration of protons and label your findings as 'C'. Now, you're close to finding the buffer capacity, so you need to locate the figure that you labeled 'B' and then divide it by the number you labeled 'C'. This will give you the amount and the type of buffer that was used in the solution to influence the capacity, and you should label it 'D'.

  • Step 4
The last step of calculating buffer capacity is to find the figure labeled 'A' and then add it to the last figure you calculated. Once you have that you should multiply the sum by 2.303 and you will have the buffer capacity.
Aisha Profile
Aisha answered
Buffer Capacity refers to the maximum amount of a strong acid or strong base that is added so that a significant change in PH occurs. Mathematically it is expresses as:
B = êB / êpH
For details on calculations see the link below:
Shayne Hutcheson Profile
Finding the maxium buffering capacity is when the pH = pKa.

In terms of graphing your data and more information in regards to the buffer capacity, you might like to go here.

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