calculate the ph of a buffer solution prepared by adding 0.397 mole of the sodium salt of a weak organic acid HA to 0.474 L of 1.023m acid HA with pka=4.82 and diluting to 1.00 L WITH WATER
calculate how many moles of Al2O3 ARE THERE IN 5.1grams of aluminium oxides
To calculate the pH of the buffer solution, we need to use the Henderson-Hasselbalch equation, which is given by:
pH = pKa + log([A-]/[HA])
where:
- pH is the measure of the acidity or alkalinity of a solution
- pKa is the negative logarithm of the acid dissociation constant (Ka) of the weak acid
- [A-] is the concentration of the conjugate base (in this case, the sodium salt of the weak acid)
- [HA] is the concentration of the weak acid
Let's calculate step by step:
Step 1: Calculate the concentration of the weak acid, HA:
Since we have 0.474 L of a 1.023 M solution of HA, we can use the equation:
[HA] = (moles of solute) / (volume of solution in liters)
[HA] = (0.474 L) x (1.023 M) = 0.485202 mol
Step 2: Calculate the concentration of the conjugate base, [A-]:
Since we added 0.397 moles of the sodium salt of the weak acid (HA), the concentration of the conjugate base can be calculated using the equation:
[A-] = (moles of solute) / (volume of solution in liters)
[A-] = (0.397 mol) / (1.00 L) = 0.397 M
Step 3: Calculate the pH using the Henderson-Hasselbalch equation:
pH = pKa + log([A-]/[HA])
pH = 4.82 + log(0.397 M / 0.485202 M)
Calculating the ratio [A-]/[HA]:
[A-]/[HA] = 0.397 M / 0.485202 M = 0.818
pH = 4.82 + log(0.818)
Using logarithmic properties, we can rewrite the equation as:
pH = 4.82 + log10(0.818)
Now, calculate the logarithm:
pH = 4.82 + (-0.089)
Finally, sum up the values:
pH = 4.731
Therefore, the pH of the buffer solution is approximately 4.731.