Answer:
The stoichiometry of an intermediate step should be manipulated in such a way that it cancels out in the overall chemical equation.
An intermediate step is a reaction that occurs during a multi-step chemical reaction but is not present in the final balanced equation. Its purpose is to facilitate the overall reaction by forming and consuming reactive intermediates.
To manipulate the stoichiometry of an intermediate step, follow these steps:
1. Identify the intermediate step in the reaction mechanism.
2. Determine the stoichiometric coefficients of the reactants and products in the intermediate step.
3. Adjust the coefficients of the intermediate step so that it cancels out when combined with the other steps in the overall reaction.
4. Ensure that the balanced equation represents the correct overall stoichiometry and conservation of mass.
For example, let's consider a simple reaction involving an intermediate step:
Step 1: A + B → C (Intermediate step)
Step 2: C + D → E (Final step)
In this case, the intermediate step is the formation of C. To manipulate the stoichiometry, we can adjust the coefficients of the intermediate step:
Step 1: A + B → C (2 moles of C formed)
Step 2: C + D → E (2 moles of C consumed)
By doubling the coefficients in Step 1, the intermediate C cancels out when combined with Step 2:
2(A + B) → 2C
C + D → E
The final balanced equation is:
A + B + C + D → E
In summary, to manipulate the stoichiometry of an intermediate step in an overall chemical equation, adjust the coefficients of the intermediate step so that it cancels out when combined with the other steps, ensuring the conservation of mass in the final balanced equation.