Final answer:
The rate of change in concentration of CO₂ when C₂H₄ is consumed at 3.6×10⁻² M/s is 7.2×10⁻² M/s. This is determined by doubling the consumption rate of C₂H₄ based on the stoichiometry of the reaction.
Step-by-step explanation:
The student has asked: If the concentration of C₂H₄ is decreasing at the rate of 3.6×10⁻² M/s, what is the rate of change in the concentration of CO₂? To solve this, we analyze the stoichiometry of the balanced combustion reaction of ethylene which is:
C₂H₄(g) + 3 O₂(g) → 2 CO₂(g) + 2 H₂O(g).
From the coefficients, we see that for every 1 molecule of C₂H₄ consumed, 2 molecules of CO₂ are produced. This means that the rate of production of CO₂ is twice the rate of consumption of C₂H₄.
Therefore, if C₂H₄ is consumed at 3.6×10⁻² M/s, the CO₂ is produced at a rate of 7.2×10⁻² M/s, since 2 times 3.6×10⁻² equals 7.2×10⁻². We express the rate in molarity per second at two significant digits as 7.2×10⁻² M/s.