Then according to your reaction, find how many moles of Sodium Diacetate are needed to get the same amount of Acetic acid you previously calculated using stochiometric ratios. Find the required mass of Sodium Diacetate by multiplying the amount of moles you calculated for Sodium Diacetate before with the molar mass of Sodium Diacetate. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.