Week Seven Flashcards
Spontaneous reactions
does it on its own
works in one direction
will not go back the other way by itself
Nonspontaneous reactions
done on purpose
Chemical thermodynamics
used to predict both the direction and extent of spontaneous chemical and physical change
Gibbs free energy
property that allows prediction at constant pressure, the energy available to do work
Heat
transfer of energy due to temperature change
Temperature
measure of average kinetic energy of particles
System
particular part of universe
Surroundings
everything surrounding the system
universe
system and surroundings
open system
can gain or lose mass and energy across boundaries
closed system
absorb and release energy but not mass across boundary
Isolated system
cannot exchange matter or energy with surroundings
internal energy (U)
sum of energies for all of the individual particles in a sample of matter
Enthalpy (H)
function related to the heat absorbed or evolved by a chemical system
Entropy (S)
meausre in the number of ways energy is distributed throughout a chemical system
State function
absolute value is dependent only on current state of a system
delta x
final value of x - initial value of x
two ways energy is exchanged into surroundings
heat and work
work
motion against an opposite force
Delta work
-p x delta volume
First law of thermodynamics
energy can be transferred between systems as either heat or work
energy can never be created or destroyed
Delta U
delta Q + delta W
Heat capacity
heat and temperature arent same thing
Delta Q = C x delta T
C
heat capacity constant
depends on size of sample
heat exchange
proportional to temperature change
Extensive property
property with a value that depends on the size of the samples
intensive property
property with a value independent of the size of the sample
intensive property: specific heat capacity
divide heat capacity (extensive property) by mass of sample to form specific heat capacity (intensive)
specific heat
C/m
specific heat capacity - Delta Q
C x m x delta T
Intensive property: molar heat capacity
divide heat capacity by molar amount of the sample to form molar heat capacity
molar heat constant
C/n
molar heat capacity - Delta Q
C x n x delta T
