Endothermic reaction
A reaction that takes in energy from the surroundings, so the temperature drops.
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Analogy
Like an ice pack that feels cold because it pulls heat from your skin.
In practice
Photosynthesis and thermal decomposition are endothermic. So are some instant cold packs.
Practice
Flashcards
- Is an ice pack that gets cold endothermic or exothermic?Endothermic. It takes in heat from its surroundings.
Questions people ask
What are examples of endothermic reactions?
Photosynthesis takes in light energy. Thermal decomposition of calcium carbonate needs constant heating. Dissolving ammonium nitrate in water makes the water cold, and sports cold packs use this. All of these take energy in from the surroundings. Cooking an egg also takes in energy, though that change is not reversible.
How would you show a reaction is endothermic in an experiment?
Put the reactants in an insulated cup and measure the temperature with a thermometer before and after mixing. If the temperature falls, the reaction took energy from the surroundings. A fall in temperature means it is endothermic. A rise means exothermic.