Molarity, Limiting Reactants, and Percent Yield

Molarity of Product

To determine the molarity of the product given the liters of solution:

1. Find the moles of the product using the limiting reactant (LR).

2. Apply the molarity formula: \text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}}

Determining Energy from Limiting Reactant

To find the energy (in kJ) from the limiting reactant:

Use the formula: \text{LR} \times \frac{\text{kJ}}{\text{mol LR}}, where LR is the limiting reactant.

This involves using the mole ratio and the given energy per mole.

Percent Yield

Formula: \text{Percent Yield} = \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100

Determining Limiting Reactant with Molarity and Volume

Given:

1. Volume of Reactant 1 with a concentration in Molarity.

2. Volume of Reactant 2 with a concentration in Molarity.

Convert volumes to liters.

Calculate moles: Moles = Volume (L) × Molarity (M).

Mole Ratio Method:

From the balanced equation, the mole ratio of Reactant 1 to Reactant 2 is a:b.

To react with x mol of Reactant 2:

\text{Moles of Reactant 1 needed} = x \text{ mol Reactant 2} \times \frac{a \text{ mol Reactant 1}}{b \text{ mol Reactant 2}}

If less moles of Reactant 1 is available than needed, Reactant 1 is the limiting reactant.

Calculating Product Formation Using the Limiting Reactant:

Using x mol of Limiting Reactant:

\text{Moles of Product} = x \text{ mol Limiting Reactant} \times \frac{c \text{ mol Product}}{b \text{ mol Limiting Reactant}}

Where c is the coefficient of the product in the balanced equation

\text{Moles of Excess Reactant reacted} = x \text{ mol Limiting Reactant} \times \frac{a \text{ mol Excess Reactant}}{b \text{ mol Limiting Reactant}}

Calculating Excess Reactant:

Remaining Excess Reactant = Initial moles - Moles reacted