Energy Flashcards
What is Energy?
the capacity to do work or supply heat
Potential Energy
stored potential
Kinetic Energy
active motion
What is the first law of thermodynamics?
Energy is conserved
it cannot be created or destroyed
it can be transferred or transformed
Enthalpy (H)
total energy of the molecule
the sum of potential and kinetic energy
types of kinetic energy
thermal
mechanical
electrical
magnetic
types of potential energy
chemical
elastic
nuclear
gravitational
true or false: strong bonds have low potential energy
true
true or false: weak bonds have high potential energy
true
name bonds that have high potential energy
C-H
C-C
how is kinetic energy measured?
temp
if an object has a low temp:
molecules are moving slowly
is cold
if an object has a high temp:
molecules are moving rapidly
is hot
Entropy (S)
the amount of disorder in a group of molecules
what is the second law of thermodynamics?
total entropy always increases in isolated systems
when does chemical equilibrium occur?
when the forward and reverse reactions proceed at the same rate
when the quantities of reactants and products remain constant
when is a chemical reaction spontaneous?
they proceed without any continuous external influence
no added energy is needed
is a spontaneous reaction fast or slow?
could be either
non-spontaneous reaction depends on:
continuous external influence
needs energy
Spontaneity of a reaction depends on
1.The change in potential energy (deltaH)
Products often have less potential
energy than the reactants (deltaH) decrease
- The degree of order (deltaS)
Products are less ordered than the
reactants (deltaS) increase
Gibbs free energy change deltaG
deltaG = deltaH-TdeltaS
deltaH : difference in enthalpy (total energy of
molecules)
deltaS : difference in entropy (disorder)
T : temperature
Spontaneous reaction (exergonic) delta G <0
Non-spontaneous reaction (endergonic) delta G>0
