In this video we will discuss about When magnesium ribbon is burning, what do you observe? Ans) #Magnesium #ribbon burns with a #dazzling flame and watch powder is collected on the watch glass placed under it. The white powder is magnesium oxide formed by the reaction of magnesium and oxygen present in the air. The burning magnesium ribbon produces #light of sufficient intensity to cause temporary loss of sight. Avoid looking directly at the light source. The burning of magnesium in air produces intense heat which can cause burns and initiate #combustion in #flammable materials. Mg burns in the air, emitting a bright white flash, and then combines with oxygen to form basic magnesium oxide. MgO is a basic element. The experiment shows that burning magnesium ribbon in air is a direct #combinationreaction. The formation of #magnesiumoxide is a chemical change.
Burning of magnesium ribbon in air is a chemical change because of the following reasons: It is an irreversible change, as after burning the ribbon cannot be unburnt. A new product is formed with new properties, i.e., [MgO]. The composition of magnesium changes.
When magnesium ribbon is burnt, it reacts with the oxygen present in the air to form magnesium oxide. The reaction occurs as follows: 2Mg (s)+O2 (g)→2MgO (g)
Symbol Mg. A light, silvery-white, moderately hard metallic element that in ribbon or powder form burns with a brilliant white flame.

Procedure

1. Impurities are removed from a piece of magnesium ribbon by rubbing it with sandpaper.

2. Use a pair of tongs to hold the magnesium ribbon over the watch glass or china dish.

3. Light the magnesium ribbon on the bunsen burner. Gather ash in a watch glass or china dish.

4. Bring the ash with moist red litmus paper.

A physical change occurs when there is no change in the composition of a substance and no change in the chemical nature of the substance.

The interconversion of state occurs during physical change.

SOLID ⇄ LIQUID ⇄ GAS

A chemical change is a change that causes a change in the chemical properties of matter, resulting in the formation of a new substance. As an example, consider the burning of oil or fuel.

Heat is evolved or taken in, the formation of bubbles, gas, and fumes, as well as a change in the colour of the reactants, can take place when they form a product.