Clarification on a group of energy concepts

isochoric/isometric: $\Delta V = 0$
isothermal: $\Delta T = 0$
isobaric: $\Delta P = 0$

Mulin_Li_2J
Posts: 105
Joined: Sat Aug 17, 2019 12:16 am

Clarification on a group of energy concepts

Hi, I know it's a lot to ask, but can anyone tell me the difference among internal energy, thermal energy, potential energy, kinetic energy, rotational energy, vibrational energy, transitional energy, enthalpy, q(under constant pressure), and q(under constant volume)?

You don't have to answer them all. Just provide the definitions you know!!!

Thanks!!!

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

Re: Clarification on a group of energy concepts

U is internal energy, meaning the energy inside of a system at a time. Is also a state function. Usually used in terms of change of internal energy, delta U

Alice Chang 2H
Posts: 101
Joined: Fri Aug 30, 2019 12:18 am

Re: Clarification on a group of energy concepts

Internal energy (ΔU): the total energy of a closed system. Internal energy is the sum of potential energy of the system and the system's kinetic energy

thermal energy: the internal energy of an object due to the kinetic energy of its atoms and/or molecules (raise in temperature leads to an increase in movement of atoms and molecules)

potential energy: energy that an object has because of its position relative to other objects, stored energy

kinetic energy: energy possessed by an object in motion

---I'm not sure about anything below this (I'm just finding stuff online)---

rotational energy: the rotation of the molecule around its center of gravity (??)

vibrational energy: energy in a vibrating system, otherwise at rest; especially that in a molecule due to the vibrations of its atoms

transitional energy: the amount of energy it takes to cause an electron to transition from one energy level to another

enthalpy: the capacity to do non-mechanical work and the capacity to release heat (basically heat)

Jasmine Kim 1L
Posts: 71
Joined: Fri Aug 02, 2019 12:16 am

Re: Clarification on a group of energy concepts

I don't think we need to know rotational, vibrational, and transitional energy. We never went over those in class from what I remember.

For q at constant pressure and constant volume, the difference is in the equation. When a rxn is under constant pressure, the equation is $q = nCp\Delta T$. Under constant volume, the equation is $q = nCv\Delta T$.