Endothermic reaction facts for kids

An endothermic reaction is a special kind of chemical reaction that takes in energy from its surroundings. Think of it like a sponge soaking up water, but instead of water, it's soaking up energy! This energy is usually heat energy. When an endothermic reaction happens, the area around it often feels cooler because the reaction is absorbing heat. The opposite of an endothermic reaction is an exothermic reaction, which releases energy.

What is an Endothermic Reaction?

An endothermic reaction is a process where chemicals combine or break apart, and during this change, they absorb energy. This energy is most often taken in as heat. Because heat is absorbed, the temperature of the surroundings usually goes down. You might even feel this temperature drop with your hand or a thermometer!

How Does It Work?

Imagine you have two chemicals that want to react. For them to change and form new substances, they need a certain amount of energy. In an endothermic reaction, they don't have enough energy on their own. So, they pull the needed energy from their environment. This makes the surroundings colder. It's like a plant taking in sunlight for photosynthesis – the plant uses the sun's energy to grow.

Some reactions are also reversible. This means the new substances formed can react again to turn back into the original ones.

Examples of Endothermic Reactions

Endothermic reactions happen all around us. Here are a few common examples:

Photosynthesis

Photosynthesis is one of the most important endothermic reactions on Earth. Plants use energy from sunlight to turn carbon dioxide and water into glucose (a type of sugar for food) and oxygen. This process absorbs light energy, making it endothermic.

Mixing Chemicals

• Ethanoic acid and sodium carbonate: When you mix ethanoic acid (which is in vinegar) with sodium carbonate (baking soda), you'll notice the mixture gets colder. This is because the reaction absorbs heat from its surroundings.
• Dissolving ammonium chloride: If you dissolve ammonium chloride in water, the water will feel much colder. This is a classic example used in science classes to show an endothermic process. The dissolving process takes in heat energy.

Thermal Decomposition

Thermal decomposition is when a substance breaks down into simpler substances because of heat. For example, if you heat calcium carbonate (found in limestone), it breaks down into calcium oxide and carbon dioxide. This process requires a continuous supply of heat, meaning it's an endothermic reaction.

Endothermic vs. Exothermic

It's helpful to compare endothermic reactions with their opposite, exothermic reactions.

• Endothermic reactions absorb energy, usually as heat, making the surroundings colder.
• Exothermic reactions release energy, usually as heat or light, making the surroundings hotter.

Think of a cold pack you use for injuries – that's an endothermic reaction making things cold. A burning fire, on the other hand, is an exothermic reaction releasing heat and light.

See also

In Spanish: Proceso endotérmico para niños