1. The problem statement, all variables and given/known data Tums react in your stomach to produce a gas. The average adult stomach expand to one liter when full. Calculate the pressure in the average adult stomach after taking 2 Tums. 2. Relevant equations Since its asking for pressure, and the volume is given perhaps PV=nRT should be used. Also P1V1=P2V2 might seem like a possible equation. 3. The attempt at a solution I'm honestly not sure how to start this problem. I started with a balanced chemical equation for the reaction of the Tums (CaCO3) and the stomach acid/hydrochloric acid (HCl), which would be: CaCO3 + 2HCl --> CaCl2 + H2O + CO2. I'm not sure where to go from here or if this is a necessary step in solving the problem. Any suggestions in where to start would be helpful.