How could some chemical changes be reversed?

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.

Use the right-hand rule for magnetic force to determine the charge on the moving particle. this is a charge.

It is really hard for me right know