Synthesis Reaction

The word 'synthesis' means to put together.

In a synthesis reaction two substances combine to produce a single product.

The general chemical equation for a synthesis reaction is A + B   AB

The reaction of a metal with a non-metal to produce a compound is an example of a synthesis reaction.

Examples of synthesis reactions

1. The burning of magnesium metal

If a piece of magnesium ribbon is ignited a very bright light is given off and a white powder or ash is produced/ Note: the burning of magnesium produces UV light which may damage the eyes if looked upon directly. Wear safety goggles and do not directly look at the light.

Magnesium + oxygen   magnesium oxide

2Mg + O₂   2MgO

2. The reaction of sodium with chlorine

If a piece of sodium metal is melted in a deflagrating spoon and placed into a gas jar containing chlorine gas a violent reaction occurs. If the jar is observed crystals of sodium chloride salt are seen which have formed on the sides of the glass.

Sodium + chlorine   sodium chloride

2Na + Cl₂   2NaCl

3. The reaction of aluminum with bromine

Aluminum is resistant towards reaction because of a tough impermeable oxide layer which strongly adheres to the metal. If however, a sheet of aluminum foil is scratched with steel wool the aluminum is exposed it will react violently with pure liquid bromine

Aluminum + bromine   aluminum bromide

2Al + 3Br₂   2AlBr₃

4. The burning of iron

A nail will not react when heated over a Bunsen burner. However, if the surface area of the iron is increased by using steel wool a reaction is seen to occur. Increasing the surface area increases the rate of reaction.

Iron + oxygen   iron(II) oxide

2Fe + O₂   2FeO