A sample consisting of 1.25 g of solid magnesium carbonate was heated to 670°C, where it decomposed. If the heating is carried out in a container fitted with a piston that was initially resting on the solid, calculate the work done by the piston on the surroundings during the complete decomposition. The pressure of the surroundings is 0.998 bar. (You can assume that the pressure in the system after the reaction is the same of the external pressure and that the gas behaves ideally.) What work would be done if the container was open to the atmosphere (i.e., no piston)?