# Problem: By what means can the internal energy of a closed system increase?

###### FREE Expert Solution

Internal energy of a system:

$\mathbf{∆}\mathbf{E}\mathbf{=}\mathbf{q}\mathbf{+}\mathbf{w}$

For heat, q:

+ q → if the system gains, takes in, or absorbs heat or energy
– q → if the system loses, evolves, gives off, or releases heat or energy

###### Problem Details

By what means can the internal energy of a closed system increase?