What are some examples of synthesis reactions?

A synthesis reaction, also known as a composition reaction, is characterized by the reaction of two or more substances chemically joining to form a single product.

Here are three examples

Magnesium metal reacts with oxygen to produce magnesium oxide

##2 Mg + O_2 -> 2MgO##

In this next example, sodium reacts with chloride to form table salt.

##2Na + Cl_2 -> 2 NaCl##

In the examples above, two different react to form a compound.

In the last example, two different react to form a new compound which is a single product.

Calcium oxide reacts with sulfur dioxide to produce calcium sulfite.

##CaO + SO_2 -> CaSO_3##