Dilution Calculations - SS1 Chemistry Lesson Note

Dilution is a fundamental process in chemistry that involves reducing the concentration of a solution by adding more solvents to it. Dilution calculations are crucial in various scientific disciplines, including chemistry, biology, and pharmacology, as they allow for the preparation of solutions with desired concentrations or the determination of the final concentration after dilution. We will delve into the principles and techniques of dilution calculations:

 

Dilution Principle:

The principle of dilution is based on the concept of the conservation of moles. According to this principle, the moles of solute before dilution are equal to the moles of solute after dilution, as long as no solute is added or removed from the system. This principle forms the foundation for dilution calculations.

 

Dilution Equation:

The dilution equation allows us to relate the initial concentration of a solution to the final concentration after dilution. The equation is as follows:

 

                                                C1V1 = C2V2

 

Where:

   C1 = Initial concentration of the solution (before dilution)

   V1 = Initial volume of the solution (before dilution)

   C2 = Final concentration of the solution (after dilution)

   V2 = Final volume of the solution (after dilution)

 

This equation states that the product of the initial concentration and volume is equal to the product of the final concentration and volume.

 

Steps for Dilution Calculations:

To perform dilution calculations, follow these steps:

 

1. Identify the initial concentration (C1) and volume (V1) of the solution before dilution.

 

1. Determine the desired final concentration (C2) and the final volume (V2) of the diluted solution.

 

1. Use the dilution equation (C1V1 = C2V2) to calculate the required volume of the initial solution (V1) or the volume of solvent to be added (V2).

 

1. Carry out the dilution by adding the calculated volume of solvent to the initial solution, resulting in the desired final volume.

 

Practical Tips for Dilution Calculations:

-       Pay attention to the units of concentration and volume to ensure consistency in calculations.

-       Use appropriate measuring tools, such as graduated cylinders or pipettes, to ensure accurate volume measurements.

-       Mix the solution thoroughly after dilution to ensure homogeneity.

 

Dilution calculations have practical applications in various scientific disciplines:

-       Chemistry: Dilution calculations are essential in preparing solutions with specific concentrations for experiments, determining the concentrations of unknown solutions, and understanding the behaviour of solutions in chemical reactions.

 

-       Biology and Biochemistry: Dilution calculations are used in preparing reagents, diluting samples for analysis, and determining the concentrations of biological molecules, such as proteins or nucleic acids.

 

-       Pharmacology and Pharmacy: Dilution calculations are crucial for compounding medications, preparing drug formulations with specific concentrations, and calculating dosages for patients.

 

-       Environmental Science: Dilution calculations are utilised in measuring the concentrations of pollutants in environmental samples and evaluating their impact on ecosystems.