A balanced chemical equation is based on

Options

A. law of conservation of mass
B. law of constant proportions
C. law of multiple proportions
D. law of combining welghts

Answer

To answer the question "A balanced chemical equation is based on?", we need to analyze the four laws mentioned in the video transcript and determine which one is primarily responsible for balancing chemical equations.

### Step-by-Step Solution:

1. **Understanding the Question**: We need to identify which law is the foundation for balancing a chemical equation.

2. **Reviewing the Four Laws**:
- **Law of Conservation of Mass**: This law states that mass can neither be created nor destroyed in a chemical reaction. Therefore, the mass of the reactants must equal the mass of the products. This principle is fundamental in balancing chemical equations.
- **Law of Constant Proportion**: This law states that a chemical compound always contains its component elements in fixed ratio by mass, regardless of the source or method of preparation. While important, it does not directly relate to the balancing of equations.
- **Law of Multiple Proportions**: This law states that when two elements combine to form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element are simple whole numbers. This law is more about the formation of compounds rather than balancing equations.
- **Law of Combining Weights (Law of Reciprocal Proportions)**: This law states that when two elements combine with a third element, they do so in a ratio of their weights that is a simple ratio. This law is also not primarily used for balancing equations.

3. **Identifying the Correct Law**:
- The **Law of Conservation of Mass** is the most relevant law for balancing chemical equations because it ensures that the total mass of reactants equals the total mass of products. This is the principle that guides the balancing process.

4. **Conclusion**: Based on the analysis, a balanced chemical equation is based on the **Law of Conservation of Mass**.

### Final Answer:
A balanced chemical equation is based on the **Law of Conservation of Mass**.

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