When calcium oxide reacts with hydrochloric acid, it undergoes a chemical reaction that produces calcium chloride and water, significantly releasing heat in the process.
This interaction is notably an exothermic reaction, meaning it releases thermal energy into the surroundings. The solid calcium oxide dissolves and reacts with the aqueous hydrochloric acid, transforming into new chemical species.
Balanced Chemical Equation
The precise chemical equation representing this reaction is:
CaO(s) + 2HCl(aq) → CaCl2(aq) + H2O(l)
Let's break down the components of this equation:
- CaO(s): This represents solid calcium oxide, often known as quicklime. It is a basic oxide.
- HCl(aq): This denotes hydrochloric acid in an aqueous (dissolved in water) solution. It is a strong acid.
- CaCl₂(aq): This is calcium chloride, formed as an aqueous solution. It is a salt.
- H₂O(l): This represents liquid water, another product of the reaction.
Key Characteristics of the Reaction
This reaction exhibits several important characteristics:
- Exothermic Nature: As explicitly stated, the reaction is exothermic. This means that when calcium oxide comes into contact with hydrochloric acid, you will observe a temperature increase in the reaction mixture as heat is liberated.
- Product Formation: The primary products are calcium chloride, which remains dissolved in the water, and water itself.
- State Changes: Solid calcium oxide reacts with aqueous hydrochloric acid to form aqueous calcium chloride and liquid water.
Summary of the Reaction
To summarize the essential aspects of the reaction:
| Aspect | Description |
|---|---|
| Reactants | Calcium Oxide (CaO), Hydrochloric Acid (HCl) |
| Products | Calcium Chloride (CaCl₂), Water (H₂O) |
| Energy Change | Exothermic (releases heat) |
| Equation | CaO(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) |
Practical Insights
When carrying out an experiment involving the reaction of calcium oxide with hydrochloric acid:
- Heat Observation: Be prepared for a noticeable rise in temperature. This heat release is a direct consequence of the reaction being exothermic.
- Dissolution: The solid calcium oxide will progressively dissolve as it reacts, forming a clear aqueous solution of calcium chloride if sufficient acid is present.
