Combination Reaction Examples:

1. Formation of Water (H2O) from Hydrogen Gas (H2) and Oxygen Gas (O2):
In this combination reaction, hydrogen gas (H2) and oxygen gas (O2) combine to form water (H2O). The chemical equation for this reaction is:
2H2(g) + O2(g) -> 2H2O(l)
This reaction is highly exothermic and releases a large amount of energy in the form of heat and light. It is a vital reaction for sustaining life on Earth, as water is essential for various biological processes.

2. Formation of Magnesium Oxide (MgO) from Magnesium (Mg) and Oxygen Gas (O2):
Another example of a combination reaction is the formation of magnesium oxide (MgO) from magnesium (Mg) and oxygen gas (O2). The chemical equation for this reaction is:
2Mg(s) + O2(g) -> 2MgO(s)
This reaction is an example of a combustion reaction, as it involves the rapid combination of magnesium with oxygen to produce magnesium oxide. It is also an exothermic reaction, releasing a significant amount of heat.
Overall, combination reactions involve the combination of two or more reactants to form a single product. These reactions are essential in various chemical processes and play a crucial role in the formation of different compounds.