The mass of nitrogen per gram in hydrazine is exactly one and half the mass of nitrogen in the compound ammonia. The fact illustrates the

Options

A. Law of conservation of mass
B. Multiple valency of nitrogen
C. Law of multiple proportion
D. Law of definite Proportion

Explanation

To solve the question regarding the mass of nitrogen in hydrazine compared to ammonia and how it illustrates a specific law in chemistry, we can follow these steps:

### Step-by-Step Solution

1. **Identify the Compounds**:
- We have two compounds: Hydrazine (N2H4) and Ammonia (NH3).
- We need to analyze the mass of nitrogen in each compound.

2. **Calculate the Molar Mass of Each Compound**:
- For Ammonia (NH3):
- Nitrogen (N) has an atomic mass of approximately 14 g/mol.
- Hydrogen (H) has an atomic mass of approximately 1 g/mol.
- Molar mass of NH3 = 14 + (3 × 1) = 17 g/mol.
- For Hydrazine (N2H4):
- Molar mass of N2H4 = (2 × 14) + (4 × 1) = 28 + 4 = 32 g/mol.

3. **Determine the Mass of Nitrogen in Each Compound**:
- In Ammonia (NH3), the mass of nitrogen per gram of the compound:
- Mass of nitrogen in NH3 = 14 g (from 1 mole of NH3) / 17 g (molar mass of NH3) = 0.8235 g of N per gram of NH3.
- In Hydrazine (N2H4), the mass of nitrogen per gram of the compound:
- Mass of nitrogen in N2H4 = 28 g (from 1 mole of N2H4) / 32 g (molar mass of N2H4) = 0.875 g of N per gram of N2H4.

4. **Compare the Mass of Nitrogen**:
- According to the problem, the mass of nitrogen in hydrazine is 1.5 times that in ammonia:
- If the mass of nitrogen in ammonia is x, then in hydrazine it should be 1.5x.
- From our calculations:
- Mass of nitrogen in NH3 = 0.8235 g
- Mass of nitrogen in N2H4 = 0.875 g
- This shows that 0.875 g is approximately 1.5 times 0.8235 g.

5. **Conclusion**:
- This relationship illustrates the **Law of Multiple Proportions**, which states that when two elements form more than one compound, the ratios of the masses of one element that combine with a fixed mass of the other element can be expressed in small whole numbers.

### Final Answer
The fact illustrates the **Law of Multiple Proportions**.