Problem: Calculate the pH when 0.98 g of CH3COONa (FW = 82.03 g/mol) is added to 38 mL of 0.500 M acetic acid, CH3COOH. Ignore any changes in volume. The Ka value for CH3COOH is 1.8 x 10-5.a. 3.88b. 3.67c. 4.21d. 4.54e. 2.31

FREE Expert Solution

We’re being asked to calculate the change in pH when 0.98 g of CH3COONa is added to 38 mL of 0.50 M acetic acid (CH3COOH) solution.

For this problem, follow these steps:

Step 1. Identify the conjugate base and weak acid

Step 2. Calculate the moles of weak acid

Step 3. Calculate the moles of conjugate base

Step 4. Calculate the pKa and pH


Step 1. The solution is composed of 0.50 M CH3COOH and 0.98 g CH3COONa .

 CH3COOH 

possess an Hion connected to a nonmetal (N) and oxygen oxyacid
▪ have an equal number of oxygens than hydrogens → weak acid

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Problem Details

Calculate the pH when 0.98 g of CH3COONa (FW = 82.03 g/mol) is added to 38 mL of 0.500 M acetic acid, CH3COOH. Ignore any changes in volume. The Ka value for CH3COOH is 1.8 x 10-5.

a. 3.88

b. 3.67

c. 4.21

d. 4.54

e. 2.31

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