The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. This means that the number of atoms of each element must be the same on both sides of the equation.
Let's analyze the given equations for the reaction of methane (CH₄) and oxygen (O₂):
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CH4 + O2 → C + 2H2O
- Reactants: 1 C (from CH₄) + 2 O (from O₂) + 4 H (from CH₄) = total 1 C, 2 O, 4 H
- Products: 1 C + 4 H (from 2H₂O) = total 1 C, 0 O, 4 H
- This equation does not conserve mass (specifically, oxygen).
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CH4 + O2 → CO2 + HO
- Reactants: 1 C (from CH₄) + 2 O (from O₂) + 4 H (from CH₄) = total 1 C, 2 O, 4 H
- Products: 1 C (from CO₂) + 1 O (from HO) + 1 H (from HO) = total 1 C, 1 O, 1 H
- This equation does not conserve mass (specifically, both oxygen and hydrogen).
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CH + O2 → CO2 + H2O
- Assuming CH refers to a carbon atom (C), this equation is not balanced. Without knowing how many hydrogen atoms are here and how they relate to the product side, we can’t conclude it demonstrates conservation.
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CH4 + O2 → CO2 + H2O
- Reactants: 1 C (from CH₄) + 2 O (from O₂) + 4 H (from CH₄) = total 1 C, 2 O, 4 H
- Products: 1 C (from CO₂) + 2 O (from CO₂) + 2 H (from H₂O) = total 1 C, 2 O, 4 H
- This equation conserves mass correctly.
The equation that demonstrates the Law of Conservation of Mass is CH4 + O2 → CO2 + H2O.
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