Which answer includes all of the following that are physical changes and no chemical changes? I. the electrolysis of molten sodium chloride to produce metallic sodium and gaseous chlorine II. the solidification of mercury by cooling III. the reaction of hydrochloric acid with calcium carbonate IV. the mixing of water with ethyl alcohol V. cutting an iron bar into small pieces

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.