When determining the mass of product used or reactant consumed, the number of moles must be determined before comparing two substances because a) moles react. b) atoms have the same mass but moles are different for each substance. c) different substances have different masses due to their atomic make-up. d) masses are the same for different substances.

moles react.

Explanation:

In a chemical reaction equation, we know that chemical species react in moles. It is actually the moles of the individual chemical species that participate in a chemical reaction and not the masses of those species.

In solving stoichiometric problems, it is mandatory to use moles as a conversion factor in calculating the mass of product formed or the mass of reactant consumed. We often read off the number of moles that reacted from the balanced reaction equation and then convert the reacting mass of species given to the number of moles of that specie that actually participated in the reaction in order to obtain any required information from a reaction.

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 answer is c i took the test