Phase Changes

[Cynthia Ulloa]

Would it be a good idea to understand 100% the phase changes graph that was shown in class?

[megansardina2G]

Yes, it is important to understand all of the parts of the phase change graph, as when you are changing between multiple phases you have to use each step. For example, if you want to go from solid to gas, you must calculate the total delta H in five steps. the mC(delta T) with the solid specific heat capacity, the m(delta H fusion), the mC(delta T) with the liquid specific heat capacity, the m(delta H vaporization) and then the mC(delta T) with the gas specific heat capacity. Adding all these values together will give the total energy/heat required. Hope this helps! (btw at the review session I went to on Saturday, the UAs said that there has been a phase change problem on every midterm/final for the past 8 years or so, so it's almost certain that it will appear again).

[whitney_2C]

Understanding it would definitely make problem solving easier so I would try to as much as you can. I took some notes in my discussion with the graph labeled, a picture of it is shown below. Hope it helps!

[Kriti Goyal 4K 19]

Yes it is very important to understand the phase changes as a lot of the times questions may ask the complete heat difference of a phase change and at the time you need to be conscious of the heat required for changing phase even though the temperature does not change.

[Cynthia Ulloa]

Understanding it would definitely make problem solving easier so I would try to as much as you can. I took some notes in my discussion with the graph labeled, a picture of it is shown below. Hope it helps!

thank you so much!

[Anna O 2C]

To add on, often times Dr. Lavelle might also ask questions that require you to "recreate" the shape of the graph and the changes occurring at each phase.

[inlovewithchemistry]

Its important to understand it when solving problems that involve phase changes, as it allows you to visualize the steps.

[Karina Jiayu Xu 4E]

It appeared on the 2019 test so I advise future students to learn it well beforehand.

[MadisonB]

I think it is useful and it eliminates confusion when doing phase change problems. I would find is pretty difficult to do they problems without having a good handle on the diagram.

[Hadji Yono-Cruz 2L]

Yes, understanding phase changes is beneficial and it is important to note that temperature is constant during a phase change.

[Pritish Patil 1K]

Yes, it is significant as many thermochemistry questions are based on this graph (ex: amt of energy needed from temp1 phase 1 to temp 2 phase 2). It is important to know this.

[Roberto Gonzalez 1L]

Yes, as well as understand how to incorporate the enthalpy of heating a substance as well as 3 step problems have been covered a lot.