## Delta U

$\Delta U=q+w$

Ellis Song 4I
Posts: 102
Joined: Thu Jul 11, 2019 12:17 am

### Delta U

What exactly is $\Delta U$? I know it means internal energy but I'm not sure what that means.

DarrenKim_1H
Posts: 123
Joined: Fri Sep 20, 2019 12:17 am
Been upvoted: 1 time

### Re: Delta U

It refers to the energy contained within a system

DarrenKim_1H
Posts: 123
Joined: Fri Sep 20, 2019 12:17 am
Been upvoted: 1 time

### Re: Delta U

So basically, U = q + w refers to the fact that it is the total energy that the system is involved with, i.e the energy from the heat generated or loss plus the energy of the work done on or against the system

805097738
Posts: 180
Joined: Wed Sep 18, 2019 12:20 am

### Re: Delta U

this is the internal energy of the system. so w would be the work either done by or on the system and q would be the heat either absorbed or given off by the system. the changes are looked at in the perspective of the system

Subashni Rajiv 1K
Posts: 101
Joined: Wed Sep 18, 2019 12:16 am

### Re: Delta U

When solving for internal energy, it is helpful to keep track of the terms given in relation to the system and not the surroundings.

Jainam Shah 4I
Posts: 130
Joined: Fri Aug 30, 2019 12:16 am

### Re: Delta U

Delta U is basically the internal energy of the system. When a system is isolated the delta U cannot change. Delta U changes by an input of energy via heat transfer or work due to compression/expansion.

Dina Marchenko 2J
Posts: 54
Joined: Thu Jul 25, 2019 12:16 am

### Re: Delta U

It's important to remember than delta U is the change in internal energy rather than just the internal energy of a system. It's a state function that looks at how the internal energy of a system changes over the course of a process (if a system releases or absorbs energy).

Rebekah Alfred 1J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am
Been upvoted: 1 time

### Re: Delta U

Changes in internal energy are a function of initial and final states. When delta U is zero, a gas still can expand because it is a spontaneous process with an entropy increase.

805383532
Posts: 53
Joined: Thu Jul 11, 2019 12:16 am

### Re: Delta U

Delta U is the change in internal energy. Internal energy is the energy contained within a system.