To determine which of the given chemical equations is unbalanced, let's analyze each equation step-by-step. A balanced chemical equation should have the same number of atoms of each element on both sides of the equation.
1. Equation: [tex]\( \mathbf{C + O_2 \rightarrow CO_2} \)[/tex]
- On the left side:
- Carbon (C): 1 atom
- Oxygen (O): 2 atoms
- On the right side:
- Carbon (C): 1 atom
- Oxygen (O): 2 atoms
This equation is balanced because both sides have 1 carbon atom and 2 oxygen atoms.
2. Equation: [tex]\( \mathbf{Sr + O_2 \rightarrow 2 SrO} \)[/tex]
- On the left side:
- Strontium (Sr): 1 atom
- Oxygen (O): 2 atoms
- On the right side:
- Strontium (Sr): 2 atoms
- Oxygen (O): 2 atoms
This equation is unbalanced because the number of strontium atoms on the left side (1 atom) does not match the number of strontium atoms on the right side (2 atoms).
3. Equation: [tex]\( \mathbf{6 H_2 + 3 O_2 \rightarrow 6 H_2O} \)[/tex]
- On the left side:
- Hydrogen (H): [tex]\( 6 \times 2 = 12 \)[/tex] atoms
- Oxygen (O): [tex]\( 3 \times 2 = 6 \)[/tex] atoms
- On the right side:
- Hydrogen (H): [tex]\[ 6 \times 2 = 12 \][/tex] atoms
- Oxygen (O): [tex]\[ 6 \times 1 = 6 \][/tex] atoms
This equation is balanced because both sides have 12 hydrogen atoms and 6 oxygen atoms.
4. Equation: [tex]\( \mathbf{H_2 + H_2 + O_2 \rightarrow H_2O + H_2O} \)[/tex]
- On the left side:
- Hydrogen (H): [tex]\( 2 \times 2 = 4 \)[/tex] atoms
- Oxygen (O): 2 atoms
- On the right side:
- Hydrogen (H): [tex]\( 2 \times 2 = 4 \)[/tex] atoms
- Oxygen (O): 2 atoms
This equation is balanced because both sides have 4 hydrogen atoms and 2 oxygen atoms.
From this analysis, the only unbalanced equation is the second one:
[tex]\[ \boxed{Sr + O_2 \rightarrow 2 SrO} \][/tex]
Therefore, the chemical equation that is unbalanced is the second equation.
