1. The problem statement, all variables and given/known data A sample consisting of 1.0 mol of calcium carbonate CaCO3(s) was heated to 800°C, when it decomposed (CaCO3 → CaO + CO2). The heating was carried out in a container fitted with a piston which was initially resting on the solid. Calculate the work done during complete decomposition at 1.0 atm. What work would be done if instead of having a piston the container was open to the atmosphere? 2. Relevant equations Expansion work against constant external pressure: w=-pex[tex]\Delta[/tex]V 3. The attempt at a solution Ok the textbook gives an example, so I tried following that. Because Vf>>Vi, and Vf=nRT/pex, then w=-pex x nRT/pex=-nRT (im assuming n is number of moles of CO2?). 1 mole of CaCO3 makes 1 mole of CO2, so plugging in numbers, I get 8.9kJ, although I dont use the 1 atm pressure at all, so I'm thinking I'm doing the second part of the question first. Any help would be appreciated.