Entropy and Gibbs Free Flashcards
definition of entropy
measurement of disorder and randomness in system
definition of standard molar entropy
entropy the substance is in its normal state 298K 10^5Pa
definition of spontaneous change
once reaction started, it tends to continue
definition of system
chemical reactants and products themselves
definition of surroundings
everything not involved in the system
what value is entropy
positive
why do gases have high entropy
lots of energy needed to make bonds
high randomness
why do diamonds have low entropy
its solid has atoms regularly arranged
the more disorder =
more positive
more gas molecules =
higher entropy
larger gas molecules =
higher entropy
standard conditions
298K (+273 to 25)
Pressure of (pa)10^5
Normal physical state
how to calculate total entropy change
total = system + surroundings
units of entropy
J/K/mol
how to calculate surroundings
-Hreaction/T
definition of standard gibbs free energy of reaction
Gibbs free energy change when the amounts of reactants shown in stoichiometric equation react under standard conditions to form products
definition of Standard Gibbs free energy of formation
Gibbs free energy change when one mole of compound is formed from its elements in their normal states under standard conditions
what value is gibbs free energy spontaneous
negative
in equilibrium what value is gibbs
0
how to calculate gibbs free energy change
Hreaction - T(Ssystem)
describe possible outcomes of value when gibbs reaction is endothermic
system is +, only spontaneous if temperature is high
system is -, not spontaneous
describe possible outcomes of value when gibbs reaction is exothermic
system is +, definitely spontaneous
system is -, only spontaneous at low temperature
what does the total energy change of gibbs free show
energy available to do work (G)
energy not available to do work (T(S))
