Which of these is true of chemical reactions? A.) all of these are true

B.) In a chemical reaction, one or more substances undergo a change in state.

C.) In a chemical reaction, one or more new substances are formed from one or more other substances.

D.) In a chemical reaction, the substances that are combined always form a gas.

it is the most commonly accepted one

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 right answer is c i just did the question.