Internal Energy

[Bradley Bohall 3L]

What actually is internal energy? How does it relate to the closed system diagram Professor Lavelle drew in class?

[Alba Mendis 1A]

According to the textbook, the exact definition of internal energy is just the total energy of a system. Closed systems can still exchange its energy with the surroundings. I'm not sure which diagram you are asking about, but I think there would be a change in the internal energy of a closed system if you heat/cool it (q) or compress/expand it (w).

[Zain Syed 1E]

Internal energy is just the total energy within a system, where it is the sum of q(energy transferred by heating/cooling) and w(energy transferred by compression/expansion). Internal energy is also a state function, so you can just use its final and initial states to find the system's internal energy.

[Gianna McNiel 1I]

Internal energy is the sum of work done on or by the system and the heat gained or released by the system. In a closed system, heat can be transferred from the system to the surroundings and visa versa, but no actual substances can be exchanged. Both q and w can still affect the internal energy in a closed system. There just wouldn't be a change in moles or grams of the substances that are part of the system/surroundings.

[Jasmine Patel 1B]

As other students have stated, the internal energy consists of the energy inside a system (and is not constant - rather is a state function). Based on my understanding, the profs examples account for the accumulation of internal energy pending the system it is placed in (open, closed, isolated) since this has an affect on the accumulation of internal energy of the system. An isolated system would see the most dramatic change in internal energy compared to an open system having the least dramatic change since it is more readily influenced by the environment. Please correct me if I am wrong.

[Ella Figueroa 2H]

I had a follow up question:

If the energy within a closed system is known as internal energy, what would you call the energy present in an open or isolated system?