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### System vs Surroundings

Posted: Tue Feb 19, 2019 10:53 am
I have a hard time determining what the system is in a reaction. Is there a way of easily identifying what it is or do we have to memorize that for certain examples one is the system and thus the other is the surroundings?

### Re: System vs Surroundings

Posted: Tue Feb 19, 2019 11:14 am
Usually, the system is the actual thing we are dealing with in the question. For example, if we are looking at the piston and identifying characteristics like work, heat, etc., the piston is the system, while the surroundings is what is supplying heat or what the system is losing heat to or the surroundings is what does work on the piston or what the piston is doing work on. I would say it is usually very easy to identify what is the system based off the question if it is not already explicitly identified.

### Re: System vs Surroundings

Posted: Tue Feb 19, 2019 11:33 am
Yes, the system vs. surrounding should not be something you have to memorize. As mentioned before, the system is simply the situation in question, such as a piston. Since the first law of thermodynamics states the conservation of energy, a change in energy of the system means a resultant change in surroundings to balance it out.

### Re: System vs Surroundings

Posted: Tue Feb 19, 2019 11:39 am
System vs. surrounding should be evident depending on the question that is given. It usually just determines whether a certain value is positive or negative in relation to the system at hand. For example, if the question states the surroundings gained x amount of energy, then energy left the system, so the energy change of the system would have to be negative while the surroundings would have a positive value in energy change.

### Re: System vs Surroundings

Posted: Tue Feb 19, 2019 11:41 am
Simply, the system is the object you are observing and the surrounding is everything else.

### Re: System vs Surroundings

Posted: Tue Feb 19, 2019 12:21 pm
system is the object, and surrounding is everything around it that can apply heat to it or lose heat.

### Re: System vs Surroundings

Posted: Mon Feb 25, 2019 2:46 pm
The system is the thing that you're observing/looking at, while the surrounding is everything else.

### Re: System vs Surroundings

Posted: Fri Mar 01, 2019 2:18 pm
The system is the "reaction" that you're observing, typically in a piston or some form of enclosed chamber. (Unless it's an open system)

The surroundings are just everything else.

### Re: System vs Surroundings

Posted: Sun Jan 26, 2020 6:35 pm
The system is the area where the reaction is occurring. The surroundings are the outside of where the reaction is occurring. Think of the reaction happening in a beaker. If the reaction is endothermic, it requires energy to come to fruition. Therefore, it will take energy from the surroundings, or outside the beaker, making the beaker feel cool on the outside. If the reaction is exothermic, it will be releasing heat into the surroundings, making the beaker feel hot.

### Re: System vs Surroundings

Posted: Tue Jan 28, 2020 10:50 pm
“The system is the part of the universe we wish to focus our attention on. In the world of chemistry, the system is the chemical reaction. For example:

2H2 + O2 ---> 2H2O

The system consists of those molecules which are reacting.

The surroundings are everything else; the rest of the universe. For example, say the above reaction is happening in gas phase; then the walls of the container are part of the surroundings.”

https://www.chemteam.info/Thermochem/Sy ... dings.html

### Re: System vs Surroundings

Posted: Tue Jan 28, 2020 11:39 pm
System is the one that you are focusing on. In most cases, it is the chemical rxn

### Re: System vs Surroundings

Posted: Wed Jan 29, 2020 1:02 pm
Jonathan Zhao 4H wrote:Yes, the system vs. surrounding should not be something you have to memorize. As mentioned before, the system is simply the situation in question, such as a piston. Since the first law of thermodynamics states the conservation of energy, a change in energy of the system means a resultant change in surroundings to balance it out.

so a piston would indicate that you are working with a closed system?

### Re: System vs Surroundings

Posted: Wed Jan 29, 2020 4:40 pm
the system is were the chemical reaction would usually occur. I don't recall Professor Lavelle mentioning needing to memorize systems and surroundings.

### Re: System vs Surroundings

Posted: Wed Jan 29, 2020 6:59 pm
Milena Aragon 2B wrote:I have a hard time determining what the system is in a reaction. Is there a way of easily identifying what it is or do we have to memorize that for certain examples one is the system and thus the other is the surroundings?

The system is where the reaction is actually occurring. The surroundings are everything else. The sum of the system and the surroundings make up the universe.

### Re: System vs Surroundings

Posted: Thu Jan 30, 2020 4:57 pm
The system is the actual reaction and the surrounding is everything else.