To carry out the Burning of magnesium ribbon in air and classify it as physical or chemical changes

To carry out the Burning of magnesium ribbon in air and classify it as physical or chemical changes

Physical Change: These changes can be observed and take place without changing the composition of substances. There are no changes in chemical nature of substance. The changes which can be observed are like change in colour, boiling point, melting point, hardness, density, fluidity, rigidity etc. The interconversion of states of matter is also a physical change.

Chemical change: In this change, chemical reaction takes place and completely a new substance with different properties is formed. There are changes in chemical properties and composition of substance.
ex: 2Mg(s) + O2(g) → 2MgO(s)
Here, the chemical composition and properties of product MgO is totally different from its reactants Mg and O.

Materials Required
Red Litmus Paper, Magnesium Ribbon

Apparatus required
China Dish or Watch Glass, Sand Paper, Tongs, Bunsen Burner, Match Box


Step 1: A piece of magnesium ribbon is taken and rubbed with sand paper to remove dust from its surface.
Step 2: Magnesium ribbon is hold with the help of a pair of tongs over the watch glass or china dish.
Step 3: Burning of magnesium ribbon over Bunsen burner is observed and ash is collected in watch glass or china dish.
Step 4: Moist red litmus paper is brought in contact with the white ash collected in watch glass.

Observation Table

Sl. No. Experiment Observation Inference
1. Magnesium ribbon is rubbed with sand paper. It looks silvery white. Colour of magnesium metal is silvery white.
2. Magnesium Ribbon is burnt. It burns brilliantly and a white ash is left behind. Magnesium burns in air to form Magnesium oxide (MgO).
3. Moist red litmus is brought in contact with the ash of Magnesium ribbon. Red litmus paper turns blue. MgO is basic in nature.

1. Magnesium is silvery white metal.
2. Magnesium burns in air in the presence of O2 to form magnesium oxide.
                  2Mg(s)    +     O2(g)     →     2MgO(s)
            (Magnesium)    (From air)    (Magnesium oxide)
3. There is direct combination reaction of two elements Mg and O2
4. Magnesium oxide(MgO) is basic in nature.
5.Formation of MgO is chemical change.

1. The surface of magnesium ribbon should be properly cleaned with sand paper.
2. The white ash of magnesium oxide should not be touched.
3. Magnesium ribbon should be held by a pair of tongs while burning it.
4. It is better to use sun glasses to protect eyes from dazzling light of burning magnesium ribbon.

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