Is the law of constant composition true for all types of compounds? Explain why or why not?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Law of Constant Composition**: The law of constant composition states that a chemical compound always contains its component elements in fixed ratio by mass, regardless of the source or how it was prepared.

2. **Isotopes and Their Impact**: Compounds can be formed from different isotopes of the same element. Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, leading to different atomic masses.

3. **Example of Carbon Isotopes**: Consider carbon, which has isotopes such as C-12 and C-14. When carbon forms compounds, the isotope used can affect the overall mass ratio of the compound.

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