Bake the baking soda in a 375F degree oven for at least 30 minutes.
Alternately put the baking soda in a non-aluminum saucepan and heat on high until no steam bubbles appear and a cold lid placed on the pan shows no signs of condensation. Heat an additional 10 minutes to insure complete conversion.
This will make anhydrous sodium carbonate with a molecular weight of 106 grams per mole. So to make a 1 Molar solution with this sodium carbonate, use 10.6 grams with enough water to make 100 ml.
