Explain Endothermic Reaction with examples?

An endothermic reaction is a chemical reaction that absorbs heat from its surroundings, resulting in a decrease in the temperature of the surroundings. In other words, energy is taken in from the environment in the form of heat during an endothermic reaction. The term "endothermic" derives from the Greek words "endo," meaning "within," and "thermos," meaning "heat."

During an endothermic reaction, the reactants require an input of energy to form the products. This energy is typically absorbed in the form of heat, but it can also come from other sources such as light or electricity. As a result, the surroundings cool down as heat is absorbed.

Here are a few examples of endothermic reactions:

Dissolution of ammonium nitrate: When solid ammonium nitrate dissolves in water, it absorbs heat from the surroundings. The reaction can be represented by the equation:

NH₄NO₃(s) + H₂O(l) → NH₄⁺(aq) + NO₃⁻(aq)

The dissolution of ammonium nitrate is commonly used in cold packs or instant ice packs, where the reaction between the solid salt and water cools down the pack.

Photosynthesis: This vital process for plants is also an endothermic reaction. In the presence of sunlight, plants convert carbon dioxide and water into glucose and oxygen. The overall reaction can be represented as:

6 CO₂(g) + 6 H₂O(l) + energy (from sunlight) → C₆H₁₂O₆(aq) + 6 O₂(g)

The absorption of light energy is necessary for this reaction to occur, and it results in the conversion of carbon dioxide and water into glucose and oxygen.

Melting of ice: The process of ice melting is an endothermic reaction. Heat from the surroundings is absorbed by the ice, resulting in a phase change from solid to liquid. The equation for the melting of ice can be represented as:

H₂O(s) + heat → H₂O(l)

The absorption of heat energy allows the ice to gain enough energy to break its intermolecular forces and transition into liquid water.

These examples demonstrate how endothermic reactions require an input of energy and result in a decrease in the temperature of the surroundings as heat is absorbed.