1. A sample consisting of 1.0 mol CaCO3 (s) was heated to 800oC when it is decomposed. The heating was carried out in a container fitted with a piston that 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?

Question

1.	A sample consisting of 1.0 mol CaCO3 (s) was heated to 800oC when it is decomposed. The heating was carried out in a container fitted with a piston that 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?

john_es · Answer

The work done is the same in the closed recipient and in the open recipient, as long as the pressure remains the same (expansion against a constant pressure,1 atm). Then, you should only calculate the work by the first process.
$$CaCO_3\rightarrow CaO+CO_2$$
So we have also 1 mol of CO_2 gas. Then the work for constant pressure is,
$$W=-PV=-nRT=-8.92\ KJ$$