U and its relations to work

[Julia Go 2L]

What does the variable U stand for and what is its relation to work?

[Cynthia Aragon 1B]

U, stands for the internal energy of a system which can be altered by heat flow and work.
If heat flows into the system; work is done on the system, and its internal energy increases, ΔU > 0.
If heat flows out of the system, work is done by the system, and its internal energy decreases, ΔU < 0

Hope this helps!

[Annalyn Diaz 1J]

Additionally in a closed system, internal energy relates to work in this equation:

delta U = q + w

[Danny Zhang 4L]

U represents the internal energy of a system. Its relation to work can be seen in the first law of thermodynamics: change in U = q(heat exchanged) + w(work done on or by the system).

[Lopez_Melissa-Dis4E]

The equation that relates U to work is delta U= q+w, U represents the change in internal energy.

[Sydney To 1D]

U is a state property and is the internal energy of a system. Changes in internal energy are a function of work. The energy of a closed system can be changed by heating/cooling or compression/expansion. U=q + w. If V is zero (constant volume), delta U= . If P=0 (constant pressure), then U=H-PV.

[Jordan Lo 2A]

What is the difference between q and delta H?

[Eruchi Okpara 2E]

Additionally, when do you know whether to use q or delta H?

[MadelynNguyen1F]

Delta H is enthalpy while q is heat flow.