What is the ratio by mass of carbon and oxygen in carbon dioxide?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 3 : 8.
The ratio by mass of carbon and oxygen in carbon dioxide (CO₂) is calculated using their atomic masses. The atomic mass of carbon (C) is 12 u, and the atomic mass of oxygen (O) is 16 u. Since CO₂ contains one carbon atom and two oxygen atoms, the total mass of the compound is 12 + (16 × 2) = 44 u. Therefore, the mass ratio of carbon to oxygen is 12:32, which simplifies to 3:8. This means for every 3 grams of carbon, there are 8 grams of oxygen in carbon dioxide by mass.