reaction feasability Flashcards
what are the general principles of entropy
gases>liquids>solids
The more complex the molecule the higher the entropy
Breaking a large molecule into smaller molecules increases the entropy
Dissolving increases entropy
define standard enthalpy of formation
the enthalpy change when one mole of substance is formed from its elements in their standard state
define standard state of a substance
its most stable state at a pressure of 1 atmosphere and at a specified temperature usually taken as 298 K
define entropy
Entropy is a measure of the degree of disorder of a system
relationship of entropy and degrees of disorder
The higher the degree of disorder the higher the entropy
what does the second law of thermodynamics state
The second law of thermodynamics states that the total energy of a reaction system and its surroundings always increases for a spontaneous process
what does the third law of thermodynamics state
the entropy of a perfect crystal at 0 K is zero. as the solid is heated it gains more kinetic energy and the entropy increases
when does a spontaneous process take place
it takes place on its own, irrespective of how long it takes and without any outside assistance
what happens if the change in free energy between reactants is negative
a reaction may occur and the reaction said to be feasible
define enthalpy of formation
the enthalpy change when one mole of a substance is formed from its elements in their standard states
do solids have high disorder
NO.
what happens to entropy as temp increases
entropy increases
what does heat energy released by the reaction system do
Heat energy released by the reaction system into the surroundings increases the entropy of the surroundings.
what happens when heat energy is absorbed by the reaction system
Heat energy absorbed by the reaction system from the surroundings decreases the entropy of the surroundings.
what is standard entropy
The standard entropy of a substance is the entropy value for the substance in its standard state.
what happens if the change in free energy (G) between reactants and products is negative
If the change in free energy (G) between reactants and products is negative, a reaction may occur and the reaction is said to be feasible
what side of equilibrium must a feasible reaction lean toward
A feasible reaction is one that tends towards the products rather than the reactants. This does not give any indication of the rate of the reaction.
If K is positive, delta G should always be …
negative
how can the feasibility of a chemical reaction under standard conditions be predicted
The feasibility of a chemical reaction under standard conditions can be predicted from the calculated value of the change in standard free
energy (G)
under non standard conditions what does G have to be for the reaction to be feasible
Under non-standard conditions any reaction is feasible if G is negative.
until when will a reverse reaction proceed
A reversible reaction will proceed spontaneously until the composition
is reached where
= G 0
at equilibrium what does G=
0
