heat capacities and enthalpy of phase changes

Moderators: Chem_Mod, Chem_Admin

Clarice Chui 2C
Posts: 101
Joined: Fri Aug 30, 2019 12:16 am

heat capacities and enthalpy of phase changes

Postby Clarice Chui 2C » Sun Feb 09, 2020 9:42 pm

What is the relationship between heat capacity equation and enthalpy of phase change equations? Some questions don't give you, for example, the enthalpy of vaporization and liquid, so what do you do to calculate the enthalpy of of vaporization? Do you use the heat capacity equation?

EvanWang
Posts: 101
Joined: Sat Sep 07, 2019 12:16 am

Re: heat capacities and enthalpy of phase changes

Postby EvanWang » Sun Feb 09, 2020 10:08 pm

I don't think there is a way to calculate enthalpy of phase changes based on the heat capacity equation. The only way I know if calculating the enthalpy of phase changes is by adding and subtracting other enthalpies of phase changes because enthalpy is a state function, for example:

Enthalpy of vaporization=enthalpy of sublimation-enthalpy of fusion

Ashley Wang 4G
Posts: 103
Joined: Wed Sep 11, 2019 12:16 am

Re: heat capacities and enthalpy of phase changes

Postby Ashley Wang 4G » Sun Feb 09, 2020 10:40 pm

The equation involving heat capacity isn't applicable to phase changes because ∆T would be zero during a phase change. I'm fairly certain the enthalpies of vaporization, fusion, etc will be given on the midterm. The ones for water are listed on the constants and equations sheet, and I imagine for any other substance it would be given in the question itself.


Return to “Heat Capacities, Calorimeters & Calorimetry Calculations”

Who is online

Users browsing this forum: No registered users and 1 guest