Two chemicals react to generate a new chemical in a combination reaction. A combination reaction is nearly always an exothermic reaction.
The combustion process is one example of a combination reaction.
When barium interacts with fluorine, however, Barium Flouride is formed, which is a highly exothermic reaction.
The reactions in which atoms or molecules combine to generate a product are known as combination reactions.
The majority of reactions involving combinations are exothermic.
Magnesium oxide reacts with carbon dioxide to generate magnesium carbonate, releasing heat in the process because this is an exothermic reaction.
MgO + CO2 MgO + CO2 MgO + CO2 MgO + CO2 MgO + CO (CO3)2
Calcium oxide (quick lime) interacts with water to form calcium hydroxide and a lot of heat.
Ca(OH)2 + heat + CaO + H2O