- Count the oxygen atoms in the reactant \(CaCO_3\), which equals 3.
- Count the oxygen atoms in the products \(CaO\) and \(CO_2\), which is \(1 + 2 = 3\).
- Compare the counts to determine that the equation is balanced.
- Conclude that the statement "balanced because the total number of oxygen atoms is 3" is correct. \(\boxed{\text{balanced because the total number of oxygen atoms is 3.}}\)
Explanation
- Analyzing the Chemical Equation
The given chemical equation for the decomposition of calcium carbonate is:
\[CaCO_3 \rightarrow CaO + CO_2\]
To determine if the oxygen atoms are balanced, we need to count the total number of oxygen atoms on both the reactant side and the product side.
On the reactant side, we have one molecule of calcium carbonate (\(CaCO_3\)). The formula \(CaCO_3\) contains 3 oxygen atoms.
On the product side, we have one molecule of calcium oxide (\(CaO\)) and one molecule of carbon dioxide (\(CO_2\)).
- Calcium oxide (\(CaO\)) contains 1 oxygen atom.
- Carbon dioxide (\(CO_2\)) contains 2 oxygen atoms.
Total oxygen atoms on the product side = (1 from \(CaO\)) + (2 from \(CO_2\)) = 3.
Comparing both sides, we have 3 oxygen atoms in the reactants and 3 oxygen atoms in the products. Since the number of oxygen atoms is equal on both sides, the oxygen atoms are balanced.
- Conclusion and Selection
Based on our count, we have:
- Reactant side: 3 oxygen atoms
- Product side: 1 + 2 = 3 oxygen atoms
The equation is balanced with respect to oxygen atoms because the total number of atoms on both sides is the same (3). Therefore, the correct statement is that the oxygen atoms are balanced because the total number of oxygen atoms is 3.
Examples
Understanding chemical balancing is fundamental to chemistry, much like balancing a budget in finance. Just as every cent must be accounted for in an account, every atom must be accounted for in a chemical reaction according to the Law of Conservation of Mass. This skill is essential for predicting the amounts of reactants needed and the yields of products in industrial manufacturing, such as producing lime (calcium oxide) for construction materials like cement.