Lecture 1/23

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Sarah_Kang_2K
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Joined: Fri Sep 28, 2018 12:23 am

Lecture 1/23

Postby Sarah_Kang_2K » Fri Jan 25, 2019 1:50 pm

Can anyone please fill me in on what Dr. Lavelle went over in class this past Wednesday? I wasn't able to make it due to traffic. Thank you in advance!

Riya Shah 4H
Posts: 65
Joined: Wed May 02, 2018 3:00 am

Re: Lecture 1/23

Postby Riya Shah 4H » Fri Jan 25, 2019 3:16 pm

hello,

he started thermochemistry and introduced enthalpy. he said that enthalpy is a state property meaning that it does not depend on the path taken but only on the initial condition. he also talked about enthalpies of fusion (solid -> liquid), sublimation (solid -> gas), and vaporization (liquid -> gas).

Michael Novelo 4G
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Joined: Fri Sep 28, 2018 12:28 am

Re: Lecture 1/23

Postby Michael Novelo 4G » Fri Jan 25, 2019 4:38 pm

In addition to what has been said he defined Enthalpy as the amount of heat released or absorbed at a constant pressure. Exothermic reactions gives off head and loses energy such as a peice of wood burning on a fire and Delta H is negative. Exothermic is he opposite. He also introduced vaporization (liquid into vapor) , melting (or fusion) (Solid to liquid) and Sublimation (Solid to Vapor) where the products are subtracted from one another using H (Enthalpy values). All these examples are Endothermic. And he went into depth in today's lecture how Hsub = Hfus + Hvap using his analogy A->B->C where you can go from A to C in one step rather than solve A to B then B to C seperately.

Carissa Young 1K
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Joined: Fri Sep 28, 2018 12:17 am

Re: Lecture 1/23

Postby Carissa Young 1K » Fri Jan 25, 2019 6:14 pm

In addition, the definition of state property is that its a value determined by its current state and is not dependent on the path taken to obtain that state. State property can be added and subtracted. Other state properties are energy, pressure, volume, temperature, density, and heat capacity.


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