Multiple Phase Changes

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Emily Vainberg 1D
Posts: 102
Joined: Sat Jul 20, 2019 12:15 am

Multiple Phase Changes

Postby Emily Vainberg 1D » Sun Feb 02, 2020 11:12 am

I watched a video online where it showed how you calculate a reaction that goes through multiple phase changes. 0 degrees to 170 degrees. In this video they had to split it up first calculating the energy from 0-100 degrees and then from 100-170 degrees. Is this something we will need to know for the test? Lavelle never mentioned it.

Edmund Zhi 2B
Posts: 118
Joined: Sat Jul 20, 2019 12:16 am

Re: Multiple Phase Changes

Postby Edmund Zhi 2B » Sun Feb 02, 2020 11:37 am

When substances change phases, their specific heats also change. If this is water, for example, the specific heats of water and steam are different and therefore need to be calculated separately and then added together for total heat added.

Hussain Chharawalla 1G
Posts: 100
Joined: Sat Jul 20, 2019 12:15 am

Re: Multiple Phase Changes

Postby Hussain Chharawalla 1G » Sun Feb 02, 2020 11:52 am

Yes, and just to add on you must also account for the specific heat of vaporization or the amount of heat to change phase from liquid to vapor.

Vinita Saxena 2I
Posts: 58
Joined: Fri Aug 09, 2019 12:16 am

Re: Multiple Phase Changes

Postby Vinita Saxena 2I » Sun Feb 02, 2020 1:41 pm

If we need to know this you'll be given the graph, just use the graph to figure out the different cutoffs to calculate the reaction changes.

Callum Guo 1H
Posts: 134
Joined: Fri Aug 02, 2019 12:15 am
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Re: Multiple Phase Changes

Postby Callum Guo 1H » Sun Feb 02, 2020 1:43 pm

You have to account for energy it takes for changes in phases and the difference in specific heat for different phases.

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