12 - Cálculo de Diluição das Soluções ( C1V1 = C2V2)

Summary

In this educational video, the presenter explains the process of calculating dilutions of solutions. The main concept focuses on how adding solvent to a concentrated solution reduces its concentration, with clear steps on using the dilution formula. Several examples, such as mixing sodium chloride solutions and preparing specific concentrations, are discussed, helping viewers understand how to adjust volumes and concentrations in real-world laboratory settings. Key concepts like concentration, volume, and molarity are highlighted, offering practical knowledge for students and lab professionals to apply in various scientific contexts.

Takeaways

• 😀 Dilution is the process of decreasing the concentration of a solution by adding a solvent, typically water, to it.
• 😀 Concentration is inversely proportional to dilution: as the volume increases with added solvent, the concentration decreases.
• 😀 The mass of solute remains constant during dilution, but the total volume increases as more solvent is added.
• 😀 The formula for dilution involves initial and final concentrations and volumes, expressed as C1 * V1 = C2 * V2.
• 😀 Volume 2 (final volume) is the sum of Volume 1 (initial volume) and the volume of the solvent added.
• 😀 The example shows that when adding 75ml of water to 25ml of a 0.12 M NaCl solution, the final concentration becomes lower than the initial concentration.
• 😀 When performing dilution calculations, the units of volume should be consistent. If different units are used, they must be converted.
• 😀 A laboratory technician may need to calculate the volume of a concentrated solution required to make a desired final concentration and volume.
• 😀 In another example, to prepare 500ml of a 1.5M NaOH solution from a 2M stock solution, the technician needs to calculate the volume of the stock solution to use.
• 😀 To solve for the required volume of the stock solution, the formula C1 * V1 = C2 * V2 is used, where C1 is the initial concentration and V1 is the volume to be calculated.
• 😀 To dilute a solution from 2M to 0.5M, the volume of solvent added can be calculated by subtracting the initial volume from the final volume, ensuring the desired concentration is achieved.

Q & A

What is the purpose of diluting a solution?

The purpose of diluting a solution is to decrease its concentration by adding more solvent. This reduces the amount of solute per unit of volume.

What happens to the amount of solute when a solution is diluted?

When a solution is diluted, the amount of solute remains the same, but the total volume of the solution increases due to the added solvent.

How is concentration related to volume in a dilution process?

Concentration is inversely proportional to volume. When you increase the volume by adding solvent, the concentration decreases.

What formula is used to calculate the dilution of a solution?

The dilution formula is C1 * V1 = C2 * V2, where C1 and V1 are the initial concentration and volume, and C2 and V2 are the final concentration and volume.

What does the formula C1 * V1 = C2 * V2 represent in dilution?

This formula represents the relationship between the initial and final concentrations and volumes. It ensures that the amount of solute remains constant before and after dilution.

In the example of diluting NaCl solution, what is the initial concentration and volume used?

In the example, the initial concentration of the NaCl solution is 0.12 mol/L, and the initial volume is 25 mL.

What is the final concentration after diluting the NaCl solution with water?

The final concentration after dilution is calculated as 0.05 mol/L, based on the formula C1 * V1 = C2 * V2.

How do you calculate the amount of solution to dilute if you need a specific final volume and concentration?

To calculate the volume needed for dilution, use the dilution formula, rearranging it to V1 = (C2 * V2) / C1, where C2 is the desired final concentration, V2 is the final volume, and C1 is the initial concentration.

What is an aliquot in the context of dilution?

An aliquot is a specific portion of a solution that is taken for further dilution or use in a procedure. It is a small, measured amount from the original solution.

How do you determine the volume of solvent to add to achieve a desired concentration?

To find the volume of solvent to add, first calculate the final volume using the dilution formula, then subtract the initial volume of the solution from the final volume.