Can someone please help me here? It's review for my test. Thanks!
Calculate the expected pH of the buffer prepared in Part I of this lab. The Ka
of acetic acid is 1.8 x 10-5
Calculate the expected pH when 10.0mL of 0.10M HCl is added to the buffer from question 3
Calculate the expected pH when 10.0mL of 0.10M NaOH is added to the buffer from question 3 (not the
one from question 4).
This is for part 1. Mix 50.0 mL of 0.20 M sodium acetate with 10.0 mL of 1.0 M acetic acid and 40.0 mL deionized water.
To calculate the expected pH of a buffer solution, you need to consider the equilibrium reaction of the acid and its conjugate base. The Henderson-Hasselbalch equation is commonly used for this calculation.
1. Calculate the expected pH of the buffer prepared in Part I of the lab:
The Henderson-Hasselbalch equation is given by:
pH = pKa + log([A-]/[HA])
Where:
pH is the expected pH of the buffer solution.
pKa is the negative logarithm (base 10) of the acid dissociation constant (Ka).
[A-] is the concentration of the conjugate base (acetate ion).
[HA] is the concentration of the acid (acetic acid).
In this case, the Ka of acetic acid is given as 1.8 x 10^-5.
2. Calculate the expected pH when 10.0 mL of 0.10 M HCl is added to the buffer from question 3:
First, you need to calculate the concentration of the acid and its conjugate base after adding the HCl. Since HCl is a strong acid, it completely dissociates in water, which means the concentration of HCl becomes 0.10 M. Calculate the new concentration of the acid and base, then use the Henderson-Hasselbalch equation to determine the expected pH.
3. Calculate the expected pH when 10.0 mL of 0.10 M NaOH is added to the buffer from question 3:
Similar to the previous step, calculate the concentration of the acid and its conjugate base after adding NaOH. Since NaOH is a strong base, it completely dissociates in water, which means the concentration of OH- becomes 0.10 M. Use this to determine the new concentration of the acid and base, and then use the Henderson-Hasselbalch equation to find the expected pH.
Remember to consider the volume of the solution when calculating concentrations.