Final answer:
To write balanced overall reactions for a mechanism, one combines individual steps, ensuring atom conservation, adjusting coefficients, and simplifying by removing common species. The equilibrium constant for the overall reaction is the product of constants from individual steps. Balancing may require additional steps in basic media by adding hydroxide ions and simplifying.
Step-by-step explanation:
The question asks to write balanced overall reactions for a multi-step chemical mechanism. This task involves understanding how to manipulate individual reactions in a mechanism to obtain the cumulative balanced equation. For instance, the information provided suggests recognizing when a reaction is a combination of prior reactions and how to calculate equilibrium constants (K) for the overall reaction by multiplying the constants from individual steps.
When balancing reactions, it is essential to ensure the number of atoms for each element is equal on both sides of the equation. For example, an unbalanced equation could start like a simple hydrocarbon combustion reaction, C2H6 + O2 → CO2 + H2O, which needs to be balanced by adjusting coefficients to satisfy the conservation of mass for each element.
Another essential step is simplifying the equation by removing species common on both sides, particularly when adding half-reactions together. In basic media, adjustments are made by adding OH- ions on both sides of the equation and combining H+ and OH- to form water, then removing redundant water molecules for a balanced chemical equation.