## Internal energy (U) of an isolated system

rkang00
Posts: 69
Joined: Fri Sep 28, 2018 12:25 am

### Internal energy (U) of an isolated system

If a system is isolated with + amount of energy, will it there be no change even after time passes?

julia_lok_2K
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Joined: Fri Sep 28, 2018 12:25 am

### Re: Internal energy (U) of an isolated system

There wouldn't be any change after time passes because it's isolated--it won't be able to exchange energy or matter with its surroundings.

Neil Hsu 2A
Posts: 61
Joined: Fri Sep 28, 2018 12:16 am

### Re: Internal energy (U) of an isolated system

The First Law of Thermodynamics states that the change in internal energy of an isolated system is 0. So to answer your question, if a system had, let's say +5kJ, after any amount of time, it will still have +5kJ.

Posts: 65
Joined: Fri Sep 28, 2018 12:17 am

### Re: Internal energy (U) of an isolated system

how we measure if a system is open, closed, or isolated is if it is able to transfer heat or work with the surroundings which is also how we measure internal energy. In the case of an isolated system it is not able to transfer either so w and q are both 0 which makes deltaU = 0

Athena L 1B
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### Re: Internal energy (U) of an isolated system

Closed systems can transfer only energy, and open systems can transfer energy and matter

EllaBerry
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### Re: Internal energy (U) of an isolated system

An isolated system will never exchange energy regardless of how much time passes.

Henry Dudley 1G
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### Re: Internal energy (U) of an isolated system

rkang00 wrote:If a system is isolated with + amount of energy, will it there be no change even after time passes?

There will be no change regardless of the amount of time passed. However, this is not the case for open and closed systems.

chrisavalos-2L
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Joined: Fri Sep 28, 2018 12:18 am

### Re: Internal energy (U) of an isolated system

There would be no change because there will be no interactions with the surroundings, therefore no energy lost or energy gained so delta U will be zero, and the U itself will be the same.

Kyither Min 2K
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### Re: Internal energy (U) of an isolated system

The internal energy of the system would not change as an isolated system doesn't exchange energy or matter with it's surroundings and based off the conservation of energy theory, if energy isn't used or exchanged, the energy will stay constant.

Jonathan Pai 2I
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Joined: Fri Sep 28, 2018 12:27 am

### Re: Internal energy (U) of an isolated system

isolated system transfers no matter or energy, so deltaU is 0, however U can have a specific value.

RachelCheung1A
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Joined: Fri Sep 28, 2018 12:19 am

### Re: Internal energy (U) of an isolated system

In an isolated system, there is no exchange of energy with surroundings and therefore the internal energy stays the same and delta U is 0

005115864
Posts: 64
Joined: Fri Sep 28, 2018 12:15 am

### Re: Internal energy (U) of an isolated system

Internal energy does not change in an isolated system since it isn't able to exchange heat with its surroundings!

Posts: 64
Joined: Fri Sep 28, 2018 12:26 am

### Re: Internal energy (U) of an isolated system

There would not be change because matter and energy is not exchanged between an isolated system and its surroundings.

Luis_Yepez_1F
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Joined: Fri Sep 28, 2018 12:18 am

### Re: Internal energy (U) of an isolated system

There is no change in energy within a closed system. Since energy can neither leave or enter the system.

Pritish Patil 1K
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Joined: Fri Sep 28, 2018 12:24 am

### Re: Internal energy (U) of an isolated system

The amount of energy would be the same as it is an isolated system.

Rhea Churi 4K
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Joined: Fri Sep 28, 2018 12:28 am

### Re: Internal energy (U) of an isolated system

An isolated system cannot exchange matter or energy so there is no change.

Nghi Nguyen 2L
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Joined: Fri Sep 28, 2018 12:18 am

### Re: Internal energy (U) of an isolated system

in an isolated system there is neither an exchange of energy nor matter

Rehan Chinoy 1K
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Joined: Fri Sep 28, 2018 12:25 am

### Re: Internal energy (U) of an isolated system

There was a question like this on the midterm -- if an isolated system has an internal energy of +5 J, then after 100 years it will have an internal energy of +5 J.