Closed System

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Victoria Luu - 1C
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

Closed System

Postby Victoria Luu - 1C » Thu Jan 31, 2019 8:23 pm

How does a sealed beaker represent a closed system? wouldn't it be isolated because it can't exchange matter and energy with its surroundings?

Lauren Ho 2E
Posts: 70
Joined: Tue Oct 09, 2018 12:16 am

Re: Closed System

Postby Lauren Ho 2E » Thu Jan 31, 2019 8:38 pm

Closed systems cannot exchange matter with their surroundings, but can exchange energy.

If a sealed beaker is heated, for instance, nothing physically can leave or enter the beaker. However, there will be a heat energy transfer.

Rhay Flores 4K
Posts: 11
Joined: Fri Sep 29, 2017 7:04 am

Re: Closed System

Postby Rhay Flores 4K » Thu Jan 31, 2019 8:56 pm

They can still exchange energy, for example if the system is heated. A system is isolated if it's also insulated well and can't exchange any heat energy with its surroundings.

Brandon Mo 4K
Posts: 70
Joined: Fri Sep 28, 2018 12:15 am

Re: Closed System

Postby Brandon Mo 4K » Fri Feb 01, 2019 1:58 am

The sealed beaker is a closed system because it can still exchange energy with surroundings. It cannot exchange matter with its surroundings because it is sealed with a fixed volume. However, energy can transfer because it is not insulated, meaning heat can be exchanged.

It's like when a sealed cup of coffee loses heat.

Ray Huang 1G
Posts: 30
Joined: Fri Sep 28, 2018 12:20 am

Re: Closed System

Postby Ray Huang 1G » Fri Feb 01, 2019 8:55 am

The sealed beaker can still exchange energy. By definition an isolated system must not exchange energy and matter. If you touch a beaker full of boiling hot water, you can feel how hot the beaker is getting. That's a closed system.

Posts: 30
Joined: Wed Nov 15, 2017 3:02 am

Re: Closed System

Postby 504909207 » Fri Feb 01, 2019 8:45 pm

Dr. Lavelle said that most of the time we will be dealing with closed systems. Does anybody know why is this?

Posts: 69
Joined: Fri Sep 28, 2018 12:26 am

Re: Closed System

Postby mbaker4E » Fri Feb 01, 2019 10:47 pm

When dealing with closed systems, you are able to assume that the number of moles remains constant. This will in most cases allow for certain equations to be utilized (such as PV= nRT and certain calorimetry problrems) in order to solve for other components of the equations. Additionally, it is much easier to define the system and the surroundings when you have a closed system.

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