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Closed System

Posted: Wed Jan 10, 2018 11:33 pm
In discussion, one of the examples for a closed system my TA used was a coolant in a refrigerator coil. Can someone explain how it functions in a manner that makes it a closed system?

Re: Closed System

Posted: Wed Jan 10, 2018 11:49 pm
Had to look up how a refrigerator works, but basically there is a compressor, and coil on the outside and inside of the fridge. Hot gaseous coolant is compressed and pushed into the coil on the outside of the fridge. When it meets the cooler temperature of a kitchen, it becomes a liquid. In liquid form, the coolant flows into the fridge and freezer and absorbs the heat inside the fridge cooling down the air. As a result, the coolant evaporates into a gas and returns to the compressor, where the process begins again.

This is a closed system because energy(heat) can be exchanged between the coolant and its surroundings(the air), but matter does not.

Re: Closed System

Posted: Sat Jan 13, 2018 12:16 am
Is a calorimeter a closed or an isolated system?

Re: Closed System

Posted: Sat Jan 13, 2018 1:07 am
I think a calorimeter is a closed system...but can anyone think of an example that works as an isolated system?

Re: Closed System

Posted: Sat Jan 13, 2018 9:12 am
A calorimeter is a closed system because it has a fixed amount of matter but can exchange energy with its surroundings. A calorimeter is not an isolated system.

Re: Closed System

Posted: Sat Jan 13, 2018 4:57 pm
An example can be found in number 8.1 from the homework, part (c). It asks what type of system is a bomb calorimeter in which benzene is burned, and the answer is an isolated system.

Re: Closed System

Posted: Sat Jan 13, 2018 5:01 pm
Another example of an isolated system from the textbook is a hot liquid poured into a thermos/container with insulated walls.

Re: Closed System

Posted: Sun Jan 14, 2018 3:32 pm
In the coil of the fridge no matter exits or enter the system but energy can enter/exit the system. In fact it is the job of the coolant to carry heat out of the fridge in order to cool the inside of the fridge.