Explain the terms with examples.
An endothermic reaction is any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur. A hallmark of this type of reaction is that it feels cold.
A good example of an endothermic reaction includes dissolving a salt. It doesn't have to be table salt, nor does the solvent need to be water.
- The reaction of barium hydroxide octahydrate crystals with dry ammonium chloride
- Dissolving ammonium chloride in water
- The reaction of thionyl chloride (SOCl2) with cobalt(II) sulfate heptahydrate
- Mixing water and ammonium nitrate
- Mixing water with potassium chloride
- Reacting ethanoic acid with sodium carbonate
- Photosynthesis (chlorophyll is used to react carbon dioxide plus water plus energy to make glucose and oxygen)