Calculate the pH of an acetic acid and sodium acetate solution?

Question

Using Henderson-Hasselbach, calculate the pH of a solution composed of 155 mL of 0.1 M acetic acid and 45 g of sodium acetate. The pKa is 4.76.

So first I found the moles of socium acetate : 45g * 1 mol/60g = .75 mol, and then I divided that by the amount of solution:

.75 mol/ .155 L = 4.84 M

pH = pKa + log [4.84]/[0.1] = 6.44

Is this correct?

Answer 1

Fine - except for the Mr of sodium acetate.

It's 82.