What is the formula to calculate enthalpy change (ΔH)?

What is the formula to calculate enthalpy change (ΔH)?

• A. ΔH = H(products) + H(reactants)
• B. ΔH = H(products) - H(reactants)
• C. ΔH = H(reactants) - H(products)
• D. ΔH = moles × temperature change

Answer: (B)

The correct formula for calculating enthalpy change (ΔH) is ΔH = H(products) - H(reactants). This equation captures the essence of how enthalpy changes in a chemical reaction are determined. In this context, H(products) refers to the total enthalpy of the products formed from the reaction, while H(reactants) refers to the total enthalpy of the reactants that were initially present. By subtracting the enthalpy of the reactants from the enthalpy of the products, you get the change in enthalpy for the reaction. A positive ΔH indicates that the reaction is endothermic (absorbing heat), whereas a negative ΔH means that the reaction is exothermic (releasing heat). This formula is fundamental in thermodynamics and is widely used in various applications in chemistry and related fields to understand reaction energetics and to calculate energy changes involved in chemical processes.

The correct formula for calculating enthalpy change (ΔH) is ΔH = H(products) - H(reactants). This equation captures the essence of how enthalpy changes in a chemical reaction are determined.

In this context, H(products) refers to the total enthalpy of the products formed from the reaction, while H(reactants) refers to the total enthalpy of the reactants that were initially present. By subtracting the enthalpy of the reactants from the enthalpy of the products, you get the change in enthalpy for the reaction. A positive ΔH indicates that the reaction is endothermic (absorbing heat), whereas a negative ΔH means that the reaction is exothermic (releasing heat).

This formula is fundamental in thermodynamics and is widely used in various applications in chemistry and related fields to understand reaction energetics and to calculate energy changes involved in chemical processes.