Use the standard enthalpies of formation for the reactants and products to solve for the δhrxn for the following reaction ca(s)+ 2h20(l) → ca(oh)2(s)+h2(g) ∆hrxn= the reaction is =

- 386.6 kJ/mol.

Explanation:

ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants)

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)].

ΔHf(Ca(OH)₂(s)) = - 985.2 kJ/mol, ΔHf(H₂)(g) = 0.0 kJ/mol, ΔHf(Ca)(s) = 0.0 kJ/mol, ΔHf(H₂O)(l) = - 285.8 kJ/mol.

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)] = [(- 985.2 kJ/mol) + (0.0 kJ/mol)] - [(0.0 kJ/mol) + 2*(- 285.8 kJ/mol)] = - 386.6 kJ/mol.

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

tell me if wrong