* Reaction: Calcium (Ca) is a highly reactive metal. When it comes into contact with water (H₂O), it undergoes a chemical reaction to form calcium hydroxide (Ca(OH)₂) and hydrogen gas (H₂).
The chemical equation for this reaction is:
Ca (s) + 2 H₂O (l) → Ca(OH)₂ (aq) + H₂ (g)
* Process:
* Calcium atoms donate electrons to the water molecules.
* This creates calcium ions (Ca²⁺) and hydroxide ions (OH⁻).
* The hydrogen atoms in water molecules gain the electrons, forming hydrogen gas (H₂).
* Observations:
* The reaction is exothermic, meaning it releases heat.
* You'll see bubbles of hydrogen gas forming.
* The calcium hydroxide solution will be basic (alkaline) due to the presence of hydroxide ions.
* The reaction is often violent and can even cause the calcium metal to ignite, producing a bright white flame.
Therefore, calcium metal does not dissolve in water in the conventional sense. It reacts with water to form new substances, resulting in a chemical change.
