To determine which balanced chemical equation matches the given reaction [tex]\( \text{Mg} + \text{O}_2 \rightarrow \text{MgO} \)[/tex], we need to ensure that the number of atoms of each element is the same on both sides of the equation.
Let's examine each of the provided equations one at a time:
### 1. [tex]\( \text{Mg} + 2 \text{O}_2 \rightarrow 4 \text{MgO} \)[/tex]
- Reactants:
- Mg: 1
- O: [tex]\(2 \times 2 = 4\)[/tex]
- Products:
- Mg: 4
- O: [tex]\(4 \times 1 = 4\)[/tex]
The magnesium atoms are not balanced: 1(on the left) ≠ 4 (on the right). Therefore, this equation is not balanced.
### 2. [tex]\( 2 \text{Mg} + 2 \text{O}_2 \rightarrow 2 \text{MgO} \)[/tex]
- Reactants:
- Mg: 2
- O: [tex]\(2 \times 2 = 4\)[/tex]
- Products:
- Mg: 2
- O: [tex]\(2 \times 1 = 2\)[/tex]
The oxygen atoms are not balanced: 4 (on the left) ≠ 2 (on the right). Therefore, this equation is not balanced.
### 3. [tex]\( 2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO} \)[/tex]
- Reactants:
- Mg: 2
- O: 2
- Products:
- Mg: 2
- O: [tex]\(2 \times 1 = 2\)[/tex]
Both the magnesium and oxygen atoms are balanced: 2 Mg on both sides and 2 O atoms on both sides. Therefore, this equation is balanced.
### 4. [tex]\( 2 \text{Mg} + 2 \text{O}_2 \rightarrow 4 \text{MgO} \)[/tex]
- Reactants:
- Mg: 2
- O: [tex]\(2 \times 2 = 4\)[/tex]
- Products:
- Mg: 4
- O: [tex]\(4 \times 1 = 4\)[/tex]
The magnesium atoms are not balanced: 2 (on the left) ≠ 4 (on the right). Therefore, this equation is not balanced.
### Conclusion
The balanced chemical equation for [tex]\( \text{Mg} + \text{O}_2 \rightarrow \text{MgO} \)[/tex] is:
[tex]\[2 \text{Mg} + \text{O}_2 \rightarrow 2 \text{MgO}\][/tex]
This corresponds to option 3.
