Question:medium

When 3.0g of carbon is burnt in 8.00g oxygen, 11.00g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00g of carbon is burnt in 50.0g of oxygen? Which law of chemical combination will govern your answer?

Updated On: Jan 19, 2026
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Solution and Explanation

We are given:

  • Mass of Carbon (C) burned = 3.0 g
  • Mass of Oxygen (O2) used = 8.0 g
  • Mass of Carbon Dioxide (CO2) produced = 11.0 g

Step 1: Determine the ratio of carbon and oxygen in the formation of CO2

From the first experiment:

The ratio of carbon to oxygen is:

\[ \frac{\text{Mass of Carbon}}{\text{Mass of Oxygen}} = \frac{3.0}{8.0} = 0.375 \]

This means for every 1 g of oxygen, 0.375 g of carbon is required.

Step 2: Use the same ratio to calculate the required mass of carbon when 50.0 g of oxygen is used.

Using the ratio:

\[ \text{Mass of Carbon} = 0.375 \times 50.0 = 18.75 \, \text{g of Carbon} \]

Step 3: Calculate the mass of CO2 produced when 3.0 g of carbon reacts with 8.0 g of oxygen.

From the given data:

The ratio of CO2 to carbon is:

\[ \frac{\text{Mass of CO}_2}{\text{Mass of Carbon}} = \frac{11.0}{3.0} = 3.67 \]

This means for every 1 g of carbon, 3.67 g of CO2 is produced.

Step 4: Calculate the mass of CO2 produced when 18.75 g of carbon reacts.

\[ \text{Mass of CO}_2 = 18.75 \times 3.67 = 68.9 \, \text{g of CO}_2 \]

Conclusion: The mass of carbon dioxide (CO2) produced when 3.0 g of carbon is burnt in 50.0 g of oxygen is 68.9 g.

The governing law for this process is the Law of Definite Proportions, which states that the mass ratio of carbon and oxygen in CO2 is constant in all samples of CO2 formed.

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