Chapter 7 - Thermo Chem Flashcards
Isolated System
The system cannot exchange energy or matter with the surrounding
Closed. System
The system can exchange energy, but not matter with the surrounding
Open system
Can exchange both energy and matter with the surrounding
Process
Any change in one or more of the systems properties.
Isothermal process
Systems temperature remains constant
Adiabatic system
A process with no heat exchange between the system in the environment
Isobaric process
A system process when the pressure remains constant
Isochoric process
The process with no change in volume of the system
Spontaneous process
A process that does not need energy from an outside source
Coupling
Non-spontaneous reactions or coupled with spontaneous ones to provide the energy needed to fulfill the process
State function
Descriptors of the system in an equilibrium state. Pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy, and entropy
Standard conditions
25 C(298K) 1atm 1M concentration The conditions in which enthalpy, entropy, and Gibbs free energy Are recorded
Standard state
The most stable form of a substance
Boiling
Rapid bubbling of the entire liquid, occurring when the entire liquid is above the boiling point, and vaporization occurs throughout the liquid.
Deposition
Opposite of sublimation, from a gas directly to a solid
Super critical fluids
A fluid gas mixture at which the fluid and gas I have identical densities. Typically at high temperature and pressure
Temperature
The average kinetic energy of the particles in a substance
Enthalpy
Thermal energy, the average kinetic energy of the particles in a substance
Heat(Q)
The transfer of energy from one substance to another. He is a process function, not a state function
Enthalpy(Delta H)
The equivalent to heat under constant pressure
Heat equation
Q=mc delta T
Heat Capacity
Mass times specific heat
Enthalpy of (fusion or vaporization) transition of transition equation
Used for the change of state of a substance.
Q=mL
L= latent heat (J/gK)
Enthalpy
Heat changes at a constant pressure
Standard and enthalpy of formation
The energy required to produce one mole of a compound from it’s elements in their standard states.
Hess’s Law
Enthalpy changes of a reaction or additive, and the pathway taken for a process does not change enthalpy
Bond enthalpies
Bond dissociation energy, the average energy needed to break a bond
The negative bond dissociation energy is the energy of formation
Standard heat of combustion
The heat change associated with the combustion of a fuel
Entropy
The measure of the spontaneous dispersal of energy at a specific temperature
Entropy is always increasing or decreasing
Increasing
Gibbs free energy
A measure of the change in enthalpy and entropy of a system as it undergoes a process
Gibbs free energy equation
Gibbs free energy = enthalpy - temperature*entropy
Gibbs free energy and spontaneity
- spontaneous
+ nonspontaneous
0 in equilibrium
Gibbs free energy equation in relation to OK equivalent
Gibbs free energy = RT *ln K equivalent
