This question concerns part 1 of this lab.You need to make a buffer solution by mixing both a weak acid and its conjugate base in the right proportions to achieve the desired pH.Your desired target pH is 5.40. You have been provided with 5.00 mL of 0.100 M acetic acid solution.How many moles of sodium acetate do you need to add to this solution to obtain a buffer solution at the desired pH? The pKa of acetic acid is 4.74.
Question
This question concerns part 1 of this lab.You need to make a buffer solution by mixing both a weak acid and its conjugate base in the right proportions to achieve the desired pH.Your desired target pH is 5.40. You have been provided with 5.00 mL of 0.100 M acetic acid solution.How many moles of sodium acetate do you need to add to this solution to obtain a buffer solution at the desired pH? The pKa of acetic acid is 4.74.
Solution
To solve this problem, we can use the Henderson-Hasselbalch equation, which is:
pH = pKa + log([A-]/[HA])
Where:
- pH is the desired pH of the solution
- pKa is the acid dissociation constant
- [A-] is the concentration of the base (sodium acetate in this case)
- [HA] is the concentration of the acid (acetic acid in this case)
We can rearrange the equation to solve for [A-]:
[A-] = [HA] * 10^(pH - pKa)
Given:
- pH = 5.40
- pKa = 4.74
- [HA] = 0.100 M (since we have 5.00 mL of 0.100 M acetic acid solution)
We can substitute these values into the equation:
[A-] = 0.100 M * 10^(5.40 - 4.74) [A-] = 0.100 M * 10^0.66 [A-] = 0.100 M * 4.47 [A-] = 0.447 M
However, we need to find the number of moles of sodium acetate, not the concentration. To find the number of moles, we can use the equation:
moles = volume (L) * concentration (M)
The volume of the solution is 5.00 mL, which is 0.005 L. So:
moles = 0.005 L * 0.447 M moles = 0.002235 moles
Therefore, you need to add approximately 0.002235 moles of sodium acetate to the solution to obtain a buffer solution at the desired pH of 5.40.
Similar Questions
This question concerns part 2 of the lab.Your target pH is still 5.40, and you are starting with 10.0 mL of 0.100 M sodium acetate solution. To create the buffer, you use a burette filled with 0.100 M HCl solution and dip a pH meter into the sodium acetate solution.You add HCl from the burette until the pH meter reads 5.40 exactly.How volume of HCl (in mL) should have been added from the burette at this point ? Please note in real life the actual volume needed may differ from the "ideal" calculated value. Report your answer to two decimal places.Answer:
Acetic acid has a pKa of 4.8. How many milliliters of 0.2 M acetic acid and 0.1 M sodium acetate are required to prepare 1 liter of 0.1 M buffer solution having a pH of 4.8? Question 7 options: 500 ml acetic acid and 250 ml sodium acetate, then 250 ml water 250 ml acetic acid and 250 ml sodium acetate, then 500 ml water 250 ml acetic acid and 500 ml sodium acetate, then 250 ml water 500 ml acetic acid and 500 ml sodium acetate
This question concerns part 1 of the lab. You mixed acetic acid and sodium acetate solutions together in the proportions calculated earlier. Although your target pH was 5.40, the actual pH of the buffer solution you created was 5.47, as measured by a pH meter.What is the % difference between the experimental pH and the target pH? Report your answer to at least one decimal place.The formula you need is as follows:
Calculate the pH of a buffer solution prepared by mixing 0.2 moles of acetic acid (CH₃COOH) and 0.2 moles of sodium acetate (CH₃COONa) in enough water to make a total volume of 1 liter. The pKa of acetic acid is 5.42.Select one:a.5.4b.5.8c.6.3d.4.5
What is the final pH of a buffer solution made by mixing 10 mL of 0.6% Acetic Acid (CH3COOH; MW = 60.05; pKa = 4.8) with 50 mL of a 1.36% Sodium Acetate (CH3COONa.3H2O; MW = 136.1) solution?pH = pka + log[salt]/[acid]4.1b.4.5c.5.15d.5.5e.9.8
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