Achemical equation can be used to solve stoichiometry problems provided that it
a. indicates only the forward reaction and not the reverse.
b. indicates that reactants are in the gas phase and are not solids or liquids.
c. includes the coefficients that are needed for balancing the equation.
d. includes the state of matter after each substance

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.