Question

What factors must be considered when creating a dilute solution from a stock solution?

Short answer

When creating a dilute solution from a stock solution, the following factors must be considered: understanding the concept of concentration, determining the desired concentration of the diluted solution, knowing the concentration of the stock solution, using the dilution equation (\(C_1V_1 = C_2V_2\)), proportionally mixing the stock solution and solvent, verifying the final concentration, considering temperature and pressure, and proper storage of the prepared diluted solution.

Step-by-step solution

1. Understanding the concept of concentration

Concentration refers to the amount of solute (the substance being dissolved) present in a given volume of solvent (the substance that dissolves the solute). It is usually measured in moles per liter (M) or grams per liter (g/L). Knowledge of concentration is essential because it determines the strength of the diluted solution.

2. Determining the desired concentration of the diluted solution

Determine the desired concentration of the final diluted solution and the volume needed for the experiment. Desired concentration represents the concentration of solute in the diluted solution. This will be used as a target to achieve the proper dilution.

3. Knowing the concentration of the stock solution

Before starting the dilution process, you must know the concentration of the stock solution. Stock solutions are usually prepared in higher concentrations for storage and convenience, which will be later diluted as needed.

4. Using the dilution equation

To find out the volume of stock solution required to prepare the desired diluted solution, use the dilution equation: \(C_1V_1 = C_2V_2\), where \(C_1\) is the concentration of the stock solution; \(V_1\) is the volume of the stock solution required; \(C_2\) is the desired concentration of the diluted solution; and \(V_2\) is the volume of the diluted solution.

5. Proportionally mixing the stock solution and solvent

Carefully measure the volume of the stock solution and the solvent needed using proper measuring equipment, such as graduated cylinders or pipettes. Mix the two solutions in the correct proportions to reach the desired concentration.

6. Verifying the final concentration

Once you have prepared the diluted solution, it's essential to verify that the final concentration matches the desired concentration. This can be done using various analytical techniques like spectrophotometry, titration, or others based on the nature of the solute.

7. Consideration of temperature and pressure

Temperature and pressure can also affect the concentration of the solution. Ensure that the solutions are under similar temperature and pressure conditions when preparing and using the diluted solution.

8. Proper storage of the prepared diluted solution

Ensure appropriate storage conditions for the prepared diluted solution. Some solutions might require refrigeration or protection from light to maintain their stability and concentration. Follow proper storage guidelines for the specific solute and solvent. By considering these factors, you will be able to accurately prepare a diluted solution from a stock solution and achieve desired experimental results.

Key concepts

Concentration

Concentration is a pivotal concept in chemistry that tells us how much solute is present in a given amount of solvent. Think of it as the strength of a solution. Common measurements of concentration are moles per liter (M) or grams per liter (g/L). Knowing the concentration helps us understand how potent a solution is and how it will react. Understanding concentration is crucial when making dilute solutions because you need to know how much solute is in both your stock and target solutions.

• The unit molarity (M) indicates moles of solute per liter of solution.
• Concentrations can also be referred to in percentage terms, like weight/volume % (w/v%) or volume/volume % (v/v%).

Knowing concentrations ensures you can adjust solutions precisely, achieving the desired chemical balance for experiments. As you measure concentration, consider temperature and pressure since they can influence results.

Dilution Equation

The dilution equation is a handy tool used to calculate how to make a diluted solution from a stock solution. It is expressed as \(C_1V_1 = C_2V_2\). In simple terms, it means that the product of the initial concentration and volume equals the product of the final concentration and volume.

• \(C_1\) is the concentration of the stock solution.
• \(V_1\) is the volume of the stock solution needed.
• \(C_2\) is the concentration of the diluted solution.
• \(V_2\) is the desired volume of the diluted solution.

Using this equation helps in planning exactly how much stock solution you'll need to achieve a target dilution, ensuring precise preparation for scientific experiments.

Stock Solution

A stock solution is a concentrated form of a solution from which dilute solutions can be made. Often, stock solutions are prepared and stored at higher concentrations to save space and simplify calculations. They allow for flexibility when a specific concentration is required for an experiment.

• Stocks are usually kept in a stable, controlled environment to maintain their concentration over time.
• They are helpful for repeatability in experiments, ensuring consistent results.

To use a stock solution, you need to know its concentration and how much you need to dilute it to get your desired concentration. Understanding the role of stock solutions is key to maintaining accuracy in chemical preparations.

Analytical Techniques

Analytical techniques are methods used to verify if the concentration of your diluted solution matches the desired level. They help ensure precision and accuracy in the lab. Common techniques include:

• Spectrophotometry: Measures how much light a solution absorbs to determine concentration.
• Titration: Uses a reaction with a known concentration to find the concentration of an unknown solution.
• Chromatography: Separates compounds to analyze concentration and other properties.

Using these techniques ensures that the final solution meets the desired specifications, confirming the effectiveness of your dilution process. Each method offers unique advantages and can be selected based on the solute’s specific properties and the required precision.