Molecules are different from atoms because they
a) have less energy
b) are much smaller
c) have unique properties
d) contain chemical bonds

Option (D) is the correct answer.

Explanation:

Molecules are defined as the substances which contain same type of elements which are chemically combined to each other.

For example, is a molecule which contains two same atoms that is, chlorine atoms.

In this molecule, the atoms are chemically combined together due to sharing of electrons. Hence, they tend to form covalent bonds.

Therefore, we can conclude that molecules are different from atoms because they contain chemical bonds.

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.