Remind me if a coffee cup calorimeter is a closed or open system

[Gauss44]

If I remember right coffee cup is closed, bomb calorimeter is isolated (the water usually being defined as part of the system), and I cannot remember a good actual example (besides the definition) of an open system.

I know this is simple, yet I'm confused. Please help!

(and feel free to correct my statement above)

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[amy_k]

Bomb calorimeters are closed - they only allow heat (energy) to be exchanged, volume is constant (isochoric)
Coffee calorimeters are isolated (only if they contain a lid that prevents gas escaping) - they keep pressure constant and allow no heat exchange ideally (adiabatic) but gases (matter) can be exchanged depending on the set-up. Isolated systems prevent both exchange of matter and energy.
An example of an open system - freely exchanging both energy and matter - is boiling a saucepan of water.

 

[Gauss44]

Bomb calorimeters are closed - they only allow heat (energy) to be exchanged, volume is constant (isochoric)
Coffee calorimeters are isolated (only if they contain a lid that prevents gas escaping) - they keep pressure constant and allow no heat exchange ideally (adiabatic) but gases (matter) can be exchanged depending on the set-up. Isolated systems prevent both exchange of matter and energy.
An example of an open system - freely exchanging both energy and matter - is boiling a saucepan of water.

Thanks, now what about a coffee cup calorimeter without a lid? Based on your answer, I'm thinking that the steam released counts as mass. Is that correct?

 

[amy_k]

Yes the escaping gas counts as matter and isolated systems do not allow exchange of either matter or energy

 

[chemtopper]

If I remember right coffee cup is closed, bomb calorimeter is isolated (the water usually being defined as part of the system), and I cannot remember a good actual example (besides the definition) of an open system.

I know this is simple, yet I'm confused. Please help!

(and feel free to correct my statement above)

You should also remember that cup calorimeter works at constant pressure .It is an isolated system in which heat and matter is not allowed to flow outside the container and works at constant pressure.However Bomb calorimeter is an isolated system which works at constant volume.

 

[chemtopper]

Thanks, now what about a coffee cup calorimeter without a lid? Based on your answer, I'm thinking that the steam released counts as mass. Is that correct?

A cup without a lid can not work like a cup calorimeter.

 

[drisaac]

That's right, the Bomb Calorimeter is only an isolated system with respect to the environment since there is no heat/matter exchange between the system and the surrounding water. The Bomb Calorimeter becomes a closed system if you don't count the surrounding environment, since there is energy flow from the rxn to the water.