Phase Changes

Moderators: Chem_Mod, Chem_Admin

itzeelpadillaDis1A
Posts: 52
Joined: Fri Sep 29, 2017 7:03 am

Phase Changes

Postby itzeelpadillaDis1A » Sat Jan 13, 2018 12:29 pm

What are the exothermic phase changes?

Sue Xu 2K
Posts: 58
Joined: Fri Sep 29, 2017 7:06 am

Re: Phase Changes

Postby Sue Xu 2K » Sat Jan 13, 2018 12:52 pm

Condensation, solidification and deposition are all exothermic phase change that release heat during the process.

Dylan Mai 1D
Posts: 70
Joined: Sat Jul 22, 2017 3:00 am

Re: Phase Changes

Postby Dylan Mai 1D » Sat Jan 13, 2018 2:42 pm

Are we supposed to know the specific terms for those phase changes listed above? Like fusion for example

Arjun Sharma 1D
Posts: 33
Joined: Fri Sep 29, 2017 7:06 am

Re: Phase Changes

Postby Arjun Sharma 1D » Sat Jan 13, 2018 3:31 pm

It would probably be a good idea to know the names of the different phase changes in case they just use the specific name w/o description in a problem @Dylan Mai 1D

Shanmitha Arun 1L
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

Re: Phase Changes

Postby Shanmitha Arun 1L » Sat Jan 13, 2018 4:02 pm

It would be best to know the enthalpy of fusion and the enthalpy of vaporization as it is used in calculations.

Christina Bedrosian 1B
Posts: 33
Joined: Fri Sep 29, 2017 7:05 am

Re: Phase Changes

Postby Christina Bedrosian 1B » Sat Jan 13, 2018 5:49 pm

An easy way to think about this is that exothermic releases heat, meaning usually involving cooling, so the phase changes being exothermic would be from gas to liquid (condensation), liquid to solid (freezing), or gas to solid.

Ishita Monga 1B
Posts: 31
Joined: Thu Jul 27, 2017 3:00 am

Re: Phase Changes

Postby Ishita Monga 1B » Sat Jan 13, 2018 7:49 pm

Sue Xu 2K wrote:Condensation, solidification and deposition are all exothermic phase change that release heat during the process.

follow up- what is deposition?

Chem_Mod
Posts: 17538
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 393 times

Re: Phase Changes

Postby Chem_Mod » Sat Jan 13, 2018 7:54 pm

An exothermic reaction is a process by which energy is outputted from the system leaving the products with less overall energy than the reactants. This includes certain phase changes (like melting and condensation) for physical changes of substances, but may also include a reaction with a negative enthalpy of reaction.

Naomi Jennings 2H
Posts: 21
Joined: Thu Jul 13, 2017 3:00 am

Re: Phase Changes

Postby Naomi Jennings 2H » Sat Jan 13, 2018 8:11 pm

Ishita Monga 1B wrote:
Sue Xu 2K wrote:Condensation, solidification and deposition are all exothermic phase change that release heat during the process.

follow up- what is deposition?

Deposition is the process of a vapor going straight from vapor to solid. It's the reverse of sublimation.

RohanGupta1G
Posts: 34
Joined: Sat Jul 22, 2017 3:00 am

Re: Phase Changes

Postby RohanGupta1G » Sat Jan 13, 2018 8:57 pm

Exothermic phase changes are ones that release heat such as a gas turning into a liquid or solid, or a liquid turning into a solid. As the temperature lowers, energy is released and the phase changes.

Michelle Lee 2E
Posts: 64
Joined: Thu Jul 27, 2017 3:01 am

Re: Phase Changes

Postby Michelle Lee 2E » Sat Jan 13, 2018 10:35 pm

Think of exothermic as something that is cooler as a result of a reaction so gas to liquid (condensation: an example is water droplets on a window from fog) and liquid to solid (freezing: ice).
Endothermic, then, would be something retaining heat like ice retaining heat and melting.

Natalie LeRaybaud 1G
Posts: 54
Joined: Thu Jul 13, 2017 3:00 am

Re: Phase Changes

Postby Natalie LeRaybaud 1G » Sat Jan 13, 2018 10:48 pm

The exothermic phase changes are the ones that occur going down a heat curve. This is because they are releasing energy during the reaction and therefore have energy as a product and have a negative delta H (enthalpy). This includes freezing, condensation, and deposition as stated above.

Gwen Peng 1L
Posts: 36
Joined: Sat Jul 22, 2017 3:01 am

Re: Phase Changes

Postby Gwen Peng 1L » Sat Jan 13, 2018 11:54 pm

Fusion, vaporization, and sublimation are endothermic processes, whereas freezing, condensation, and deposition are exothermic processes.

Michelle Lu 1F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 1 time

Re: Phase Changes

Postby Michelle Lu 1F » Sun Jan 14, 2018 1:30 am

Exothermic reactions release heat, and therefore the product will be colder. This means that the exothermic phase changes are going down the heat curve, including freezing, condensation, and deposition.


Return to “Phase Changes & Related Calculations”

Who is online

Users browsing this forum: No registered users and 1 guest