1. Naturally occurring chlorine molecules, Cl2, have masses of 70, 72 and 74 amu as seen in the mass spectrum above. They occur in the percentages 56.25%, 37.50% and
6.250% respectively. Use this data to calculate the average atomic mass of chlorine
atoms and to find the relative abundance of 35Cl and "CI isotopes.

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.

the answers are

c and c