Reaction: A + 2B → C

Given:
- Moles of A = 5
- Moles of B = 8

Explanation:

To determine the amount of C formed, we need to find the limiting reagent. The limiting reagent is the reactant that is completely consumed in the reaction and determines the amount of product formed.

Step 1: Calculate the moles of C produced by A and B individually:

Since the balanced equation shows that 1 mole of A reacts with 2 moles of B to produce 1 mole of C, we can use the stoichiometric coefficients to calculate the moles of C produced.

Moles of C produced by A = 5 moles of A × (1 mole of C / 1 mole of A) = 5 moles of C

Moles of C produced by B = 8 moles of B × (1 mole of C / 2 moles of B) = 4 moles of C

Step 2: Determine the limiting reagent:

To determine the limiting reagent, we compare the moles of C produced by A and B. The reactant that produces the lesser amount of C is the limiting reagent.

In this case, B produces 4 moles of C, while A produces 5 moles of C. Therefore, B is the limiting reagent.

Step 3: Calculate the amount of C formed:

Since B is the limiting reagent, the amount of C formed is determined by the moles of C produced by B. We can use the stoichiometric coefficient to convert moles of C to the amount of C formed.

Amount of C formed = 4 moles of C × (molar mass of C / 1 mole of C)

Conclusion:

The amount of C formed by starting the reaction with 5 moles of A and 8 moles of B is determined by the limiting reagent, which is B. Using the stoichiometric coefficient, the amount of C formed can be calculated.