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An exothermic reaction is a type of chemical reaction that releases energy in the form of heat. This process occurs when the energy needed to break the bonds in the reactants is less than the energy released when the new bonds form in the products. - This difference in energy results in a net release of energy, often felt as an increase in temperature in the surroundings.- In the decomposition of potassium chlorate, as described in the exercise, heat is released, making it an exothermic reaction. The indication that a reaction is exothermic is often given by the negative sign in the heat term, - For instance, in the thermochemical equation \(2 \text{KClO}_3 (s) \rightarrow 2 \text{KCl} (s) + 3 \text{O}_2 (g) \quad \Delta H = -78.0 \text{ kJ}\)- The negative \(\Delta H\) shows that 78.0 kJ of heat is released, which verifies the exothermic nature of the reaction.

A balanced chemical equation is crucial for accurately representing a chemical reaction. It ensures that the number of atoms for each element is conserved in a chemical process. - This means the same number of each type of atom must be present on the reactant side and the product side of the equation. For the decomposition of potassium chlorate:- The balanced equation is \(2 \text{KClO}_3 (s) \rightarrow 2 \text{KCl} (s) + 3 \text{O}_2 (g)\)- This tells us that we start with two moles of potassium chlorate to produce two moles of potassium chloride and three moles of oxygen gas.Balancing equations involves adjusting the coefficients (numbers in front of molecules) to ensure each element is represented equally on both sides. - Writing a balanced equation helps in predicting the amounts of reactants needed and products formed in a chemical reaction.

The heat term in a thermochemical equation represents the amount of energy released or absorbed during a chemical reaction. It is denoted by \(\Delta H\), which stands for the change in enthalpy.- In cases where heat is released, \(\Delta H\) is negative, signifying an exothermic reaction.- When heat is absorbed, \(\Delta H\) is positive, indicating an endothermic reaction. In the context of the potassium chlorate decomposition:- The heat term \(-78.0 \text{ kJ}\) reveals that 78.0 kJ of energy is released as heat.- This helps chemists understand the energy requirements or releases associated with a reaction.Including the heat term in the thermochemical equation not only gives quantitative information about the energy change but also the nature of the reaction, - Indicating whether it is exothermic or endothermic.