Which balances the equation [tex]Mg + O _2 \rightarrow MgO[/tex]?
[tex]Mg +2 O _2 \rightarrow 4 MgO[/tex]
[tex]2 Mg +2 O _2 \rightarrow 2 MgO[/tex]
[tex]2 Mg + O _2 \rightarrow 2 MgO[/tex]
[tex]2 Mg +2 O _2 \rightarrow 4 MgO[/tex]
Answer (1)
Analyze each option by counting the number of atoms of each element on both sides of the equation.
Option 1 is not balanced: M g + 2 O 2 → 4 M g O (1 Mg, 4 O → 4 Mg, 4 O).
Option 2 is not balanced: 2 M g + 2 O 2 → 2 M g O (2 Mg, 4 O → 2 Mg, 2 O).
Option 3 is balanced: 2 M g + O 2 → 2 M g O (2 Mg, 2 O → 2 Mg, 2 O).
Option 4 is not balanced: 2 M g + 2 O 2 → 4 M g O (2 Mg, 4 O → 4 Mg, 4 O).
The balanced equation is 2 M g + O 2 → 2 M g O .
Explanation
Problem Analysis We are given the unbalanced chemical equation M g + O 2 → M g O and four possible balanced equations. Our task is to identify the equation where the number of atoms for each element is the same on both sides of the arrow.
Checking Each Option Let's examine each option:
Option 1: M g + 2 O 2 → 4 M g O Left side: 1 Mg atom, 4 O atoms Right side: 4 Mg atoms, 4 O atoms This equation is not balanced because the number of Mg atoms is not the same on both sides.
Option 2: 2 M g + 2 O 2 → 2 M g O Left side: 2 Mg atoms, 4 O atoms Right side: 2 Mg atoms, 2 O atoms This equation is not balanced because the number of O atoms is not the same on both sides.
Option 3: 2 M g + O 2 → 2 M g O Left side: 2 Mg atoms, 2 O atoms Right side: 2 Mg atoms, 2 O atoms This equation is balanced because the number of Mg and O atoms are the same on both sides.
Option 4: 2 M g + 2 O 2 → 4 M g O Left side: 2 Mg atoms, 4 O atoms Right side: 4 Mg atoms, 4 O atoms This equation is not balanced because the number of Mg atoms is not the same on both sides.
Conclusion Only option 3 has the same number of Mg and O atoms on both sides of the equation. Therefore, the balanced equation is 2 M g + O 2 → 2 M g O .
Examples
Balancing chemical equations is crucial in many real-world applications, such as in the manufacturing of pharmaceuticals, fertilizers, and other chemical products. For example, in the production of magnesium oxide ( M g O ), it's important to ensure the correct ratio of magnesium ( M g ) and oxygen ( O 2 ) to achieve the desired product and avoid waste. This ensures that the reaction proceeds efficiently and safely, leading to a high-quality product.
