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phase change

Posted: Fri Mar 13, 2020 2:30 am
how can you tell if there has been a phase change?

Re: phase change

Posted: Fri Mar 13, 2020 8:22 am
Usually the problem will tell you when a phase change occurs, or if on a phase diagram the temperature remains constant but enthalpy increases, the energy in crease was used for the phase change of the compound.

Re: phase change

Posted: Fri Mar 13, 2020 8:39 am
Like the diagram in class, you can tell that there is a phase change when the heat or enthalpy is increasing, but the temperature is not increasing, or delta T is zero.

Re: phase change

Posted: Fri Mar 13, 2020 10:02 am
Sanjana Borle 2K wrote:Like the diagram in class, you can tell that there is a phase change when the heat or enthalpy is increasing, but the temperature is not increasing, or delta T is zero.

Can the enthalpy increase AND the temperature remains the same while there still not being a phase change? Like I'm imagining the enthalpy of water at a positive value but without becoming a gas? Is that possible?

Re: phase change

Posted: Sat Mar 14, 2020 12:22 pm
KBELTRAMI_1E wrote:
Sanjana Borle 2K wrote:Like the diagram in class, you can tell that there is a phase change when the heat or enthalpy is increasing, but the temperature is not increasing, or delta T is zero.

Can the enthalpy increase AND the temperature remains the same while there still not being a phase change? Like I'm imagining the enthalpy of water at a positive value but without becoming a gas? Is that possible?

I was wondering the same thing. Would any change in either of these, no matter to what degree, result in a phase change? Or is there an explicit threshold for each phase with regards to the reaction?

Re: phase change

Posted: Sun Mar 15, 2020 6:29 am
KBELTRAMI_1E wrote:
Sanjana Borle 2K wrote:Like the diagram in class, you can tell that there is a phase change when the heat or enthalpy is increasing, but the temperature is not increasing, or delta T is zero.

Can the enthalpy increase AND the temperature remains the same while there still not being a phase change? Like I'm imagining the enthalpy of water at a positive value but without becoming a gas? Is that possible?

I was wondering the same thing. Would any change in either of these, no matter to what degree, result in a phase change? Or is there an explicit threshold for each phase with regards to the reaction?

I believe because enthalpy is a state function there are explicit thresholds for each phase which is why, when plotted, it is a step diagram. That is how I understood it, there could be a different explanation

Re: phase change

Posted: Sun Mar 15, 2020 7:48 am
Julia Holsinger_1A wrote: