How much baking soda should I mix with 1 cup of vinegar to get the best results?
One cup of vinegar (about 236 mL) contains 5% acetic acid, about 11.8 mL. For argument’s sake and simpler calculations, I’ll assume this is 12 grams of acetic acid. There are 60 grams / mole acetic acid, so there are 0.2 moles acetic acid in one cup. Acetic acid reacts one mole to one mole with sodium bicarbonate (baking soda) to produce the CO2 that makes model volcanoes work; therefore, you need to add 0.2 moles, or 16.8 grams baking soda. 16.8 grams of baking soda is half a tablespoon. But for best results, use a full tablespoon (baking soda supplies the CO2, so it should be added in excess, but not too much — a level tablespoonful should do). Put the baking soda in just enough hot water to fully dissolve the powder, then mix. Good luck!
