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### Isolated System

Posted: Thu Jan 21, 2016 5:45 pm
Based on the first law of thermodynamics, can we assume that even after an infinite amount of time, ΔU in an isolated system is 0?

### Re: Isolated System

Posted: Thu Jan 21, 2016 6:02 pm
As long as it is an isolated system, ΔU should be zero because no heat can flow in or out, and no external force can be applied.

### Re: Isolated System

Posted: Fri Feb 01, 2019 12:53 pm
An isolated system is defined as a thermodynamic system in which neither energy or matter can be exchanged with the surroundings. Work and heat can be done within the system, but this must be distinguished with whether or not there is a CHANGE in the internal energy within the system. The first law of thermodynamics states that energy is conserved within a system. In an isolated system, energy is converted from one form to another but never leaves the system. So yes, no matter what time, an isolated system will show no change in internal energy.

### Re: Isolated System

Posted: Fri Feb 01, 2019 12:54 pm
An isolated system is defined as a thermodynamic system in which neither energy or matter can be exchanged with the surroundings. Work and heat can be done within the system, but this must be distinguished with whether or not there is a CHANGE in the internal energy within the system. The first law of thermodynamics states that energy is conserved within a system. In an isolated system, energy is converted from one form to another but never leaves the system. So yes, no matter what time, an isolated system will show no change in internal energy.

### Re: Isolated System

Posted: Sat Feb 02, 2019 2:20 am
Does an isolated system have a fixed volume?

### Re: Isolated System

Posted: Sun Feb 03, 2019 5:00 pm
ΔU is zero because it can't be heated and no material can be added. Therefore, there's no work nor is there q.