I've just cooked a freshly opened one pound box of baking soda in a convection oven at 350 degrees F for a little over an hour (I poured it outinto a baking dish and stired gently every fifteen minutes or so). Now, if I understand correctly, I have a little less than a pound of Sodium Carbonate (anhydrous). Right? How can I test this? Damn! I should have worn a dust mask...(cough, cough....aarrrrgh).