- Examine each chemical equation individually by counting the number of atoms for every element present on both the reactant and product sides.
- Equation 1 (\(Mg_3N_2 + H_2O \rightarrow 3MgO + 2NH_3\)) is unbalanced because hydrogen and oxygen atoms do not match.
- Equation 2 (\(C_3H_8 + 5O_2 \rightarrow H_2O + 3CO_2\)) is unbalanced because hydrogen and oxygen atoms do not match.
- Equation 3 (\(Zn + 2HCl \rightarrow ZnCl_2 + H_2\)) is correctly balanced as all atom counts match on both sides.
- Equation 4 (\(3H_2SO_4 + 2Fe \rightarrow Fe_2(SO_4)_3 + H_2\)) is unbalanced because hydrogen atoms do not match.
- The balanced equation is: \(\boxed{Zn + 2HCl \rightarrow ZnCl_2 + H_2}\).
Explanation
- Analysis of Balancing Chemical Equations
To determine which chemical equation is balanced, we must verify that the number of atoms of each element is the same on both the reactant side (left side) and the product side (right side). A chemical equation is balanced when the Law of Conservation of Mass is satisfied, meaning mass (and therefore the number of atoms of each element) is neither created nor destroyed during the reaction.
- Evaluating the Equations
Let's analyze each equation individually:
- \(Mg_3N_2 + H_2O \rightarrow 3MgO + 2NH_3\)
- Magnesium (Mg): 3 on the left, 3 on the right. (Balanced)
- Nitrogen (N): 2 on the left, 2 on the right. (Balanced)
- Hydrogen (H): 2 on the left, 6 on the right. (Unbalanced: \(2
eq 6\))
- Oxygen (O): 1 on the left, 3 on the right. (Unbalanced: \(1
eq 3\))
This equation is unbalanced.
- \(C_3H_8 + 5O_2 \rightarrow H_2O + 3CO_2\)
- Carbon (C): 3 on the left, 3 on the right. (Balanced)
- Hydrogen (H): 8 on the left, 2 on the right. (Unbalanced: \(8
eq 2\))
- Oxygen (O): 10 on the left, 7 on the right. (Unbalanced: \(10
eq 7\))
This equation is unbalanced.
- \(Zn + 2HCl \rightarrow ZnCl_2 + H_2\)
- Zinc (Zn): 1 on the left, 1 on the right. (Balanced)
- Hydrogen (H): 2 on the left, 2 on the right. (Balanced)
- Chlorine (Cl): 2 on the left, 2 on the right. (Balanced)
This equation is balanced.
- \(3H_2SO_4 + 2Fe \rightarrow Fe_2(SO_4)_3 + H_2\)
- Iron (Fe): 2 on the left, 2 on the right. (Balanced)
- Hydrogen (H): 6 on the left, 2 on the right. (Unbalanced: \(6
eq 2\))
- Sulfur (S): 3 on the left, 3 on the right. (Balanced)
- Oxygen (O): 12 on the left, 12 on the right. (Balanced)
This equation is unbalanced.
- Conclusion
After checking each equation, we find that the equation \(Zn + 2HCl \rightarrow ZnCl_2 + H_2\) has an equal number of atoms for every element involved on both sides. Therefore, it is the only balanced equation in the list. The final answer is the third equation.
Examples
Balancing chemical equations is essential for scientists to determine how much of each reactant is needed to produce a specific amount of product. For example, if you are making a simple chemical compound for a school experiment, you would use a balanced equation like \(Zn + 2HCl \rightarrow ZnCl_2 + H_2\) to calculate exactly how many grams of Zinc (Zn) and Hydrochloric acid (HCl) are required to produce a certain volume of Hydrogen gas (\(H_2\)) safely without wasting materials or creating harmful byproducts. Accurate calculations ensure efficiency and safety in laboratory practices.