You are given a colored solution that is labeled 1M. You need to prepare a solution from this that is 0.5 M. Describe your procedure in detail.
Hey drbob222,
Instead of being condescending toward Ruch, how about actually help out, jerk.
To prepare a 0.5 M solution from a 1M colored solution, follow these steps:
1. Determine the volume of the 0.5 M solution you want to prepare. Let's say you need to prepare 500 mL of 0.5 M solution.
2. Calculate the amount of solute needed. Molarity (M) is defined as the number of moles of solute per liter of solution. Since you want to prepare a 0.5 M solution, you need a concentration half as much as the 1M solution. This means you will need to dilute the 1M solution by a factor of 2.
The equation for dilution is:
C1 * V1 = C2 * V2
Where:
C1 = initial concentration (1M)
V1 = initial volume of the solution to be diluted (unknown)
C2 = final concentration (0.5M)
V2 = final volume of the solution to be prepared (500 mL or 0.5 L)
Rearranging the equation to solve for V1, we get:
V1 = (C2 * V2) / C1
Substituting the known values:
V1 = (0.5M * 0.5 L) / 1M
= 0.25 L
= 250 mL
So, you need to measure 250 mL from the 1M solution.
3. Take a clean container, such as a graduated cylinder or volumetric flask, and measure 250 mL (or the calculated volume) of the 1M solution using a pipette or measuring cylinder. Transfer this volume to the container.
4. Once you have transferred the measured volume of the 1M solution into the container, add enough solvent (usually water or a specified solvent) to reach the desired final volume. In this case, add enough solvent to make a total volume of 500 mL (final volume) in your container.
5. Thoroughly mix the solution by gently swirling or stirring it.
6. Your solution is now ready. Label it clearly with the concentration (0.5M) and any other relevant details.
Note: When diluting concentrated solutions, always add the concentrated solution to the solvent rather than the other way around to avoid splash-back or other safety hazards. Also, use proper equipment and techniques to ensure accurate measurements and avoid contamination.