If a typical tablet contains 2.0 g of sodium hydrogen carbonate how many miles of CO2 should one tablet yeild?

I'm guessing you mean "how many moles of CO2."

There are also 84g of sodium bicarbonate in one mole. First, find how many moles of sodium bicarbonate you have in the tablet.

2/84 = ~.024 moles of sodium bicarbonate.

One mole of sodium hydrogen carbonate, or sodium bicarbonate, is equal to one mole of CO2.

This means you have ~.024 moles of CO2 in one tablet.