Synthesis reaction

The word synthesis means to put together. In a synthesis reaction two elements combine to produce a compound. A + B => C

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 alumnium 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