The pH of a 25.0 mL sample of a buffer changed by one unit when 4.19 mL of 0.24 M HCl was added to it. What is the acid buffer capacity of this buffer?
The buffer capacity = mols acid/base needed to change the pH of a L of the buffer by 1 unit.
molos added = 0.00419L x 0.24M = ?
Then ?/25 mL x (1000/25) = mols to change 1L by 1 units = ?
You can put this into equatio form with mL as mLacid x Macid/mL buffer = 4.19 x 0.24/25.00 = 0.0402
To find the acid buffer capacity of this buffer, we need to first understand the concept of buffer capacity.
Buffer capacity refers to the ability of a buffer solution to resist changes in pH when an acid or a base is added. Specifically, acid buffer capacity refers to the ability of a buffer to resist changes in pH caused by the addition of an acid.
In this case, we have a buffer solution that changed its pH by one unit when 4.19 mL of 0.24 M HCl was added. The pH change caused by the addition of the acid can be used to determine the acid buffer capacity of the buffer solution.
The acid buffer capacity (β) can be calculated using the formula:
β = Δn / ΔpH
Where:
Δn = moles of acid added
ΔpH = change in pH
To calculate Δn (moles of acid added), we need to use the concentration of HCl and the volume of HCl added. We can use the following formula to calculate the moles of acid added:
moles of acid added = concentration of acid × volume of acid added
Using the given values:
concentration of HCl = 0.24 M
volume of HCl added = 4.19 mL (convert to liters by dividing by 1000)
Δn = (0.24 M) × (4.19 mL / 1000)
Next, we need to calculate ΔpH (change in pH). In this case, the pH changed by one unit.
Now, we can calculate the acid buffer capacity (β) using the formula:
β = Δn / ΔpH
Substitute the values we calculated:
β = (moles of acid added) / (change in pH)
Now, calculate the values and substitute them into the formula to find the acid buffer capacity of the buffer solution.