All samples of carbon dioxide contain carbon and oxygen in the mass ratio of `3:8` This is in agreement with the law of .

Options

A. conservation of mass
B. constant proportion
C. multiple proportions
D. gaseous volumes

Answer

To solve the question regarding the mass ratio of carbon and oxygen in carbon dioxide (CO₂) and its relation to a specific law, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements in Carbon Dioxide**:
Carbon dioxide (CO₂) consists of two elements: carbon (C) and oxygen (O).

2. **Determine the Atomic Masses**:
- The atomic mass of carbon (C) is approximately 12 grams/mole.
- The atomic mass of oxygen (O) is approximately 16 grams/mole. Since there are two oxygen atoms in CO₂, the total mass of oxygen in CO₂ is 2 × 16 = 32 grams/mole.

3. **Calculate the Mass Ratio**:
- The mass of carbon in CO₂ = 12 grams.
- The mass of oxygen in CO₂ = 32 grams.
- The mass ratio of carbon to oxygen = mass of carbon / mass of oxygen = 12 g / 32 g = 3 / 8.

4. **Relate to the Law**:
- The question states that all samples of carbon dioxide contain carbon and oxygen in the mass ratio of 3:8.
- This consistent ratio across different samples supports a specific scientific principle.

5. **Identify the Relevant Law**:
- The law that states that a chemical compound always contains its constituent elements in fixed proportions by mass is known as the **Law of Definite Proportions**.

### Final Answer:
The mass ratio of carbon to oxygen in carbon dioxide being 3:8 is in agreement with the **Law of Definite Proportions**.

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