Stoichiometry of complete combustion: For complete oxidation, 1 kg of carbon forms how many kilograms of carbon dioxide (CO2)?

Introduction / Context:
Combustion stoichiometry uses atomic/molecular mass ratios to relate fuel mass to product mass. For elemental carbon burned to carbon dioxide, the mass ratio follows directly from molecular weights and is frequently used in flue-gas calculations and emissions estimates.

Given Data / Assumptions:

• C + O2 → CO2 (complete combustion).
• Atomic mass: C = 12; Molecular masses: O2 = 32, CO2 = 44.
• No side products (no CO or unburned C) in the ideal case.

Concept / Approach:
Balance the reaction stoichiometrically and use molecular masses. One mole of carbon (12 kg per 1000 moles basis) combines with one mole of oxygen gas (32) to produce one mole of carbon dioxide (44). Hence, per unit mass of carbon, product mass is scaled by 44/12.

Step-by-Step Solution:

Verification / Alternative check:
Carbon content and ultimate analysis in fuels often use this factor to estimate theoretical CO2 emissions from complete combustion.

Why Other Options Are Wrong:

• 3/7, 7/3, 3/11: Do not match the stoichiometric mass ratio derived from molecular weights.

Common Pitfalls:
Confusing mole ratio (1:1) with mass ratio (44:12); forgetting that oxygen mass comes from O2 in air, not from the carbon itself.

Final Answer:
11/3