We can solve the problem by using the first law of thermodynamics:
[tex] \Delta U= Q-W [/tex]
where
[tex] \Delta U [/tex] is the variation of internal energy of the system
Q is the heat added to the system
W is the work done by the system
In this problem, the variation of internal energy of the system is
[tex] \Delta U=U_f-U_i=134 J-87 J=47 J [/tex]
While the heat added to the system is
[tex] Q=500 J [/tex]
therefore, the work done by the system is
[tex] W=Q-\Delta U=500 J-47 J=453 J [/tex]
