Which of the following describes a compound? A.
a piece of pure carbon, containing only carbon atoms
B.
oxygen gas surrounding a solid piece of carbon
C.
a substance made of two oxygen atoms for each carbon atom
D.
carbon and oxygen atoms mixed without being bonded together

Explanation:

D.

carbon and oxygen atoms mixed without being bonded together

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.

you need to have a picture of the atom that way we can answer it