Dilution Calculations: Determining the Original Molarity of a KOH Solution

Introduction

Dilution calculations are an essential part of chemistry, particularly in laboratory settings where precise concentrations of solutions are crucial. This article will guide you through the process of determining the original molarity of a KOH solution when a specific volume is needed to achieve a particular concentration. We will walk through a step-by-step example and explain the underlying principles involved.

The Dilution Formula

The dilution formula, C1V1 C2V2, is used to solve for the original concentration of a solution when it is diluted. Here, C1 is the original concentration, V1 is the original volume, C2 is the final concentration, and V2 is the final volume.

A Step-by-Step Example

Suppose you need 50.0 mL of a KOH solution to dilute it to a final concentration of 3.00 M with a final total volume of 100.0 mL. To find the original molarity, follow these steps:

Step 1: Convert Volumes from mL to L

The conversion factor from mL to L is 1 L 1000 mL.

V1 50.0 mL × (1 L / 1000 mL) 0.0500 L V2 100.0 mL × (1 L / 1000 mL) 0.1000 L

Step 2: Plug the Values into the Dilution Equation

Using the dilution formula:

C1 × 0.0500 L 3.00 M × 0.1000 L

Step 3: Calculate the Right Side

Rearrange the equation to solve for C1:

C1 × 0.0500 0.300 M

Step 4: Solve for C1

C1 0.300 M / 0.0500 L

Step 5: Final Calculation

C1 6.00 M

Conclusion

The original molarity of the KOH solution is 6.00 M. This example highlights the importance of understanding and applying the dilution formula correctly. By following these steps, you can determine the original concentration of a solution even when it has been diluted.

Additional Tips

Always ensure that all volumes are converted to liters before performing the calculation. Double-check your units to avoid calculation errors. Practice different scenarios to solidify your understanding of dilution calculations.

Understanding and applying the dilution formula is a fundamental skill in chemistry and can be applied to a wide range of laboratory and industrial settings. By mastering these calculations, you can accurately prepare solutions and ensure the best possible results in your experiments.