Question

.Magnesium ribbon burns in air and changes to white substance, i.e. magnesium oxide. When
magnesium oxide dissolves in water, what type of change takes place? Give reason in support
of your answer. Express the change in the form of equation

Answer 1

Dear Student,

Magnesium ribbon reacts with oxygen to form magnesium oxide.
The reaction represented as follows:
2Mg_(s) + O_{2 (g)} = 2MgO _(s) + Energy
Thus, when magnesium is burnt in air, it forms magnesium oxide in the form of white ash. When magnesium oxide dissolves in water, it forms a new substance, magnesium hydroxide. So, it is a chemical change.
MgO_(s) + H₂O_(l) = Mg(OH)_{2 (s)}
As new substance is being formed so its a chemical change. A chemical change happens when one chemical substance is transformed into one or more different substances, such as when magnesium is burnt, new product in form of ash is formed. Chemical changes occur through the process of chemical reactions, and the resulting substances (ash) have different properties because their atoms and molecules are arranged differently.
Regards

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