Is Sublimation Endothermic or Exothermic

Sublimation is an endothermic process. This means it requires energy to happen. During sublimation, a solid changes directly into a gas without becoming a liquid first. For this to occur, the solid must absorb heat energy from its surroundings.

This heat energy helps the particles in the solid move faster and break free from their fixed positions. As the solid gains enough energy, the bonds between its particles weaken, and the particles escape directly into the air as gas. Since energy is going into the substance, sublimation is endothermic.

A great example is dry ice, which is frozen carbon dioxide. When you place dry ice on a surface at room temperature, it doesn’t melt. Instead, it disappears into gas. This happens because the dry ice absorbs heat from the air around it. That heat gives the carbon dioxide molecules enough energy to break free from the solid and spread out as gas.

You can compare this to boiling water, which is also endothermic. Just like water needs heat to turn into steam, a solid needs heat to turn directly into gas during sublimation.

Fun Fact: If you touch dry ice, it can burn your skin! That’s because it absorbs heat so quickly from your skin during sublimation.