Types of reactions:

Students of grade 7 were taken to the laboratory to perform experiments on the topic types of reactions.

Students were divided into groups of two, each performing a different experiment.

Two types of reactions were demonstrated followed by practicals.

1) Synthesis reaction is a type of reaction in which new matter is added to the original substance and the substance gains in mass.

A representation of the reaction is as follows:

A + B → AB

A magnesium wire was burnt in a Bunsen burner, using a pair of tongs to obtain a white colored powder of magnesium oxide.

Mg + O2 → MgO

2) Decomposition reaction is a type of reaction in which a single compound is broken down in a chemical reaction into two or more simpler substances.

A representation of the reaction is as follows:

A B → A + B

A small amount of green colored copper carbonate was heated in a test tube to obtain carbon di oxide and a black colored copper oxide as the products. A burning splinter was introduced into the test tube to confirm the release of carbon di oxide gas. This gas has the property of extinguishing a flame, hence the burning splinter goes off when introduced into the test tube.

This was their first experience in the chemistry laboratory so they had a lot of apprehensions about performing the experiments. However, when they started doing the experiments, they developed confidence and were able to attain the results with precision.

Performing these experiments helped them to observe the end point of the reaction through a color change and understand the property of carbon di oxide gas. They also got to know about precautions to be taken while performing the experiments.