Gases A(g) and B(g) are confined in a cylinder and piston arrangement and react to form a solid product C(s): A(g)+B(g)--C(s).

Gases A(g) and B(g) are confined in a cylinder and piston arrangement and react to form a solid product C(s): A(g)+B(g)-->C(s). As the reaction occurs, the system loses 1250 J of heat to the surroundings. The piston moves downward as the gases react to form a solid. As the volume of the gas decreases under the constant pressure of the atmosphere, the surroundings do 580J of work on the system. what is the change in the internal energy of the system?