energetically favourable :
If a ball is placed at the top of a hill and given a very small
displacement it will tend to move to the bottom of the hill
This is because at the bottom the potential energy is a minimum and
hence more stable.
entropy
A measure of the disorder in a system.
If your desk is neat and organized - you can say the entropy is low
whearas if it is unorganized and there is stuff scattered all
over the place you can say the entropy is high.
The Second Law of Thermodynamics says that the entropy of
the Universe always increases
ester
Compounds that are formed by the reaction of alchohols and acids
with the elimination of a water molecule. e.g ethyl-acetate