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What is the predicted product from the following combination reaction? CA (s) + O2 (g)
a. Cano
b. Ca2O3
c. CaO2
d. Ca3O2
e. Ca2O
The correct answer and explanation is:
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Chemistry Question:
The predicted product from the combination reaction between calcium (Ca) and oxygen (O₂) is:
e. CaO
Explanation:
1. Understanding the Reactants:
Calcium (Ca) is an alkaline earth metal that is highly reactive, particularly with oxygen. When exposed to oxygen, calcium reacts to form an ionic compound. Oxygen (O₂) is a diatomic molecule that tends to gain electrons to achieve a stable electron configuration.
2. Type of Reaction:
This is a combination reaction where two reactants combine to form a single product. The general form of a combination reaction is:
A+B→ABA + B \rightarrow AB
In this case, calcium (Ca) reacts with oxygen (O₂):
2Ca (s)+O2(g)→2CaO (s)2 \text{Ca (s)} + \text{O}_2 \text{(g)} \rightarrow 2 \text{CaO (s)}
3. Product Formation:
Calcium forms a +2 charge (Ca²⁺) as it loses two electrons to achieve a stable noble gas configuration. Oxygen forms a -2 charge (O²⁻) by gaining two electrons. These ions combine in a 1:1 ratio to produce calcium oxide (CaO), which is a neutral compound.
4. Incorrect Options:
- a. CaNO: This is not a valid compound for this reaction.
- b. Ca₂O₃: This compound does not exist under normal conditions.
- c. CaO₂: Calcium peroxide forms only under specific conditions, not in a simple reaction with oxygen.
- d. Ca₃O₂: This is not a stable or recognized compound.
5. Properties of Calcium Oxide (CaO):
- Known as quicklime or burnt lime.
- A white, crystalline solid used in construction (e.g., making cement).
- Reacts with water to form calcium hydroxide (slaked lime), releasing heat.
This reaction exemplifies how alkaline earth metals interact with oxygen to form stable oxides.