Final answer:
The relative rate of change of [C] in the reaction A + 4B → 2C, with a given rate of disappearance of A at 0.420 M/s, is calculated to be 0.840 M/s.
Step-by-step explanation:
The question concerns the relative rates of change of species in a chemical reaction. When we have the stoichiometric equation A + 4B → 2C, where the rate of disappearance of A is given as 0.420 M/s, the relative rates of reaction for B and C can be calculated based on stoichiometry.
To find the rate of disappearance of B, we multiply the rate of disappearance of A by its stoichiometric coefficient, since 4 moles of B are consumed for every 1 mole of A. Therefore, the rate of disappearance of B is 4 times 0.420 M/s, which is 1.680 M/s.
Similarly, for C, since 2 moles of C are produced for every mole of A reacted, we multiply the rate of disappearance of A by the stoichiometric coefficient of C. That gives us the rate of appearance of C, which is 2 times 0.420 M/s, equating to 0.840 M/s. Thus, the relative rate of change of [C] in the reaction A + 4B → 2C is 0.840 M/s.