Okuzeka
Chemistry vocabulary · Energy, Reaction Rates and Equilibrium

Exothermic

Meaning in chemistry, with examples

/ˌeksəʊˈθɜːmɪk/adjectiveCore term

In chemistry, exothermic means: Describes a reaction or process that releases heat to the surroundings, so the temperature rises. Its enthalpy change (ΔH) is negative.

In Turkish: ekzotermik, ısı veren

How it is used

Important for safety and energy calculations. Combustion, neutralization and dissolving NaOH in water are exothermic. When a reaction is strongly exothermic, you add reagents slowly or cool the flask.

Example sentences

  1. The reaction is highly exothermic, so add the acid slowly in an ice bath.

  2. Is dissolving ammonium nitrate in water exothermic or endothermic?

Common collocations

  • highly exothermic
  • exothermic reaction
  • strongly exothermic
  • exothermic process
  • endothermicDescribes a reaction or process that takes in heat from the surroundings, so the surroundings get colder. Its enthalpy change (ΔH) is positive.
  • enthalpyThe heat content of a system at constant pressure. Chemists usually measure its change, ΔH, which shows how much heat a reaction gives out or takes in.
  • activation energyThe minimum energy that reacting particles need to collide successfully and start a reaction. Catalysts work by lowering it.
  • chemical reactionA process in which substances change into new substances with different properties, as bonds between atoms break and new bonds form.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Energy, Reaction Rates and Equilibrium

Practise with graded reading

Reading at the right level is the fastest way to make new words stick. Pick free English books by level: