Answer:
22.4 g
Explanation:
Calculate the mass of sodium acetate that must be added to 500.0 mL of 0.300 M acetic acid to form a pH = 5.00 buffered solution.
Step 1: Given data
Volume of solution: 500.0 mL
[acetic acid]: 0.300 M
pH = 5.00
pKa of acetic acid: 4.74
Step 2: Calculate the concentration of sodium acetate
We will use the Henderson-Hasselbach equation.
pH = pKa + log [sodium acetate]/[acetic acid]
5.00 = 4.74 + log [sodium acetate]/0.300 M
[sodium acetate] = 0.546 M
Step 3: Calculate the moles of sodium acetate
We have 500.0 mL of a 0.546 M sodium acetate solution
0.5000 L × 0.546 mol/L = 0.273 mol
Step 4: Calculate the mass of sodium acetate
The molar mass of sodium acetate is 82.03 g/mol.
0.273 mol × 82.03 g/mol = 22.4 g
