Calculating Concentrations in a Buffer Solution

In summary, the conversation discusses the creation of a buffer solution using 50mL of 0.05M ethanoic acid and 50mL of 0.05M sodium ethanoate. The question is asking for the concentration of ethanoic acid and ethanoate ions in the solution, which was initially assumed to be 0.05M. However, after seeking help, it was suggested to use the Henderson-Hasselbalch equation to find the concentration of ethanoate ions first and then calculate the acid concentration. The pKa value of ethanoic acid is given as 4.76 and it is noted that pH=pKa may be relevant. However, it is clarified that there is no need
  • #1
adhlpi
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Homework Statement [/b]
A buffer solution was made using 50mL of 0.05M of ethanoic acid and 50mL 0.05 of sodium ethanoate. The question asks what is the concentration of ethanoic acid and ethanoate ions in the buffer solution. I assumed it would be 0.05M but when I asked for help I was told to work out the ethanaote ions by using Henderson-Hasselbalch equation first then work out the acid concentration. The pKa value of ethanoic acid is 4.76. I guess its something to do with the fact pH=pKa maybe, then find out the [H+]? so 10*-4.76 as my concentration
 
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  • #2
No need for HH equation here, but once you mix 50 mL with 50 mL final concentrations are not 0.05M. Think simple dilution.
 

1. What is a buffer solution?

A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added to it. It is made up of a weak acid and its conjugate base, or a weak base and its conjugate acid.

2. Why is buffer solution calculation important?

Buffer solution calculation is important because it allows scientists to prepare solutions with a specific pH. This is essential in many experiments and processes, as a slight change in pH can significantly affect the outcome. Buffer solutions help maintain a stable pH and prevent drastic changes in the system being studied.

3. How do you calculate the pH of a buffer solution?

The pH of a buffer solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]). Here, pKa is the acid dissociation constant of the weak acid in the buffer, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the weak acid. Alternatively, you can use a pH meter to directly measure the pH of the solution.

4. What factors affect buffer solution calculation?

The main factors that affect buffer solution calculation are the concentration of the weak acid and its conjugate base, as well as the pKa value of the weak acid. Temperature can also have an impact on the pH of a buffer solution, as some weak acids may become more or less dissociated at different temperatures.

5. How do you prepare a buffer solution?

To prepare a buffer solution, you need to mix a weak acid or base with its conjugate base or acid in a specific ratio. You can calculate the required amounts using the Henderson-Hasselbalch equation or use a buffer solution calculator. Once you have the correct amounts, simply mix the components together in a container to create the buffer solution.

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