1. a reaction that absorbs energy 1 endothermic 2. a reaction that releases heat precipitate 3. the amount of heat released or absorbed by a reaction 2 exothermic 4. the solid formed as a result of chemicals reacting together from a solution enthalpy

1. a reaction that absorbs energy → exothermic

2. a reaction that releases heat → endothermic

3. the amount of heat released or absorbed by a reaction → enthalpy

4. the solid formed as a result of chemicals reacting together from a solution → precipitate

Explanation:

Endothermic reaction : It is defined as the chemical reaction in which the energy is absorbed from the surrounding.

In the endothermic reaction, the energy of reactant are less than the energy of product.

Exothermic reaction : It is defined as the chemical reaction in which the energy is released into the surrounding.

In the exothermic reaction, the energy of reactant are more than the energy of product.

Enthalpy : It is defined as the amount of heat released or absorbed by a chemical reaction.

Precipitation reaction : It is defined as the reaction in which an insoluble salt formed when two aqueous solutions are combined.

The insoluble salt that settle down in the solution is known an precipitate.