Provide an example of the enthalpy and entropy of a reaction.

An example of the enthalpy and entropy of a reaction is the combustion of methane.

The combustion of methane is an exothermic reaction, meaning it releases heat energy. The enthalpy change (ΔH) for this reaction is negative, indicating that energy is being released. The equation for the combustion of methane is:

CH4 + 2O2 → CO2 + 2H2O

The enthalpy change for this reaction is -890 kJ/mol, meaning that 890 kJ of energy is released for every mole of methane that is burned.

The entropy change (ΔS) for this reaction is positive, indicating that the disorder or randomness of the system increases. This is because there are more molecules on the product side of the equation than on the reactant side. The increase in entropy is due to the formation of more gas molecules, which have more freedom of movement than the solid or liquid molecules in the reactants.

The entropy change for this reaction is 186 J/K/mol, meaning that the disorder of the system increases by 186 J/K for every mole of methane that is burned.

Overall, the combustion of methane is an exothermic reaction that releases heat energy and increases the disorder of the system.