Page 1 of 1

### Closed vs. Isolated

Posted: Sun Jan 14, 2018 2:33 pm
It is sometimes confusing to determine whether a system is a closed or isolated. How do we differentiate the two? I get that in a closed sytem, a matter cannot enter or leave it, but how do we know that if a system is not necessarily isolated?

### Re: Closed vs. Isolated

Posted: Sun Jan 14, 2018 2:36 pm
A closed system allows heat transfer, but does not allow mass transfer. An isolated system allows neither heat nor mass transfer.

### Re: Closed vs. Isolated

Posted: Sun Jan 14, 2018 2:39 pm
A closed system has a fixed amount of matter within it, but it can exchange energy with its surroundings. Isolated systems can exchange neither energy or matter with its surroundings, essentially having no contact with its surroundings.

### Re: Closed vs. Isolated

Posted: Sun Jan 14, 2018 3:06 pm
You can just simply look at exercise 8.1 to help understand it.
A closed system is when heat is exchangeable but not mass, for example, the mercury in a thermometer. Mercury is sealed in the thermometer, but the temperature will change with the heat supplied. So it is a closed system but not an isolated system.
An isolated system is when neither heat nor mass is exchangeable with the environment. A bomb calorimeter in this question, which also mentioned in the lecture, is a good example. The heat is only released in its interior.

### Re: Closed vs. Isolated

Posted: Sun Jan 14, 2018 4:11 pm
Here is the chart our TA showed us in discussion:

Isolated: Heat Transfer [ ] Mass Transfer [ ]
Closed: Heat Transfer [ X ] Mass Transfer [ ]
Open: Heat Transfer [ X ] Mass Transfer [ X ]

Hope this helps!