1. What is an Exothermic Reaction?

An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy.

2. How Does the Calculator Work?

The calculator uses the exothermic reaction equation:

Where:

• \( \Delta H \) — Enthalpy change (J)
• Negative value indicates heat released to surroundings

Explanation: For exothermic reactions, the enthalpy change (ΔH) is negative because the system loses energy to the surroundings.

3. Importance of ΔH Calculation

Details: Calculating enthalpy change is crucial for understanding reaction thermodynamics, predicting reaction feasibility, and designing chemical processes with proper heat management.

4. Using the Calculator

Tips: Enter the heat released in joules. The calculator will compute the negative enthalpy change (ΔH) value characteristic of exothermic reactions.

5. Frequently Asked Questions (FAQ)

Q1: Why is ΔH negative for exothermic reactions?
A: The negative sign indicates that energy is released from the system to the surroundings, decreasing the system's enthalpy.

Q2: What are common examples of exothermic reactions?
A: Combustion, neutralization, respiration, and many oxidation reactions are exothermic.

Q3: How is heat released measured experimentally?
A: Calorimetry is the primary method, using devices like bomb calorimeters to measure heat changes in reactions.

Q4: Can exothermic reactions be dangerous?
A: Yes, highly exothermic reactions can lead to thermal runaway, explosions, or fires if not properly controlled.

Q5: How does temperature affect exothermic reactions?
A: According to Le Chatelier's principle, increasing temperature favors the reverse (endothermic) reaction in exothermic processes.