Calculate the change in internal energy of a system if 25000 J of heat is added to the system while the system does 40000 J of work on its surroundings. Does this represent an increase or decrease of internal energy?
To calculate the change in internal energy of a system, we can use the First Law of Thermodynamics, which states that the change in internal energy is equal to the heat added to the system minus the work done by the system on its surroundings.
In this case, the heat added to the system is +25,000 J (positive because heat is being added to the system), and the work done by the system is -40,000 J (negative because work is being done by the system).
Using the equation:
Change in internal energy = Heat added - Work done
Change in internal energy = +25,000 J - (-40,000 J)
Change in internal energy = +25,000 J + 40,000 J
Change in internal energy = +65,000 J
The positive value indicates that the internal energy of the system has increased.