Theromodymamic Laws

I. the total amount of energy in the universe is constant. Energy cannot be created or destroyed vut only converted from one form into another. If an object or process gains an amount of energy, it does so at the expense of a loss in energy somewhere elesin the universe


II. the entropy of the universe increases with any change that occurs.  DS_universe  > 0

III. absolute zero is removal of all thermal molecular motion

In any chemical reactions, the output of energy will exceed the input of energy. Just like investing money into an account, a portion of money is used to make more money as in chemcial reactions the energy is put into something that will yield more energy in the end as a result. 
For example, cellular respiration shown in the diagram. The first part of the reaction is an anatabolic process which energy is used as activaion. Free energy is put into to break glucose and later combined with oxygen to produce carbon dioxide, water and ATP for body function.  The second part of the reaction is a catabolic process. Through the process, the reaction yields greater free energy than the free energy used for synthesis them. More energy means more entorpy. While the reaction is in progress the energy is released and result in the total free engergy less than 0.  Thus, DG< 0.

 
ex. glucose+ oxygen = carbon dioxide + water