Entropy Flashcards
What is entropy?
A measurement of disorder
The higher the disorder….
The higher the entropy.
What is entropy symbol?
S
How does raising the temperature of a substance affect its entropy?
Raising the temperature of a substance increases its disorder which increases its entropy
When a substance changes state what happens to entropy?
If it changes from solid to liquid entropy increases.
If it changes from liquid to gas its entropy increases even more.
If two substance are in the same state can you predict their entropy?
No only if they are in different states.
Eg. One lis liquid and one is solid
How does dissolving a solid affect its entropy?
Dissolving a solid in water increases its entropy as it becomes aqueous.
How does increasing the number of particles in the reaction affect entropy?
more products than reactants= higher entropy
one reactant breaking down into two or more products makes a higher entropy.
How does you find entropy change?
entropy change= heat/temperature
what is the entropy of substances at zero kelvin?
zero
this is because the particles aren’t moving so therefore no zero disorder.
define the standard molar entropy
the entropy of one mole of a substance at 298K
If a reaction is exothermic what happens?
it increases the entropy of the surrounding and therefore entropy change will be positive.
If a reaction is endothermic, what happens?
it decreases the entropy of the surrounding so therefore entropy change is negative.
For any reaction to occur, what does the entropy change have to be?
entropy change has to be positive.
when are reactions feasible
if the entropy of the universe increases
