You have a large amount of 8.00 M stock solution. You need 1.60 L of 3.00 M solution for an experiment. How would you prepare the desired solution without wasting any stock solution?
See Damon's response below.;
To prepare the desired solution without wasting any stock solution, you can use the concept of dilution. Dilution involves adding a solvent (usually water) to a concentrated solution to decrease its concentration while keeping the number of moles of solute constant. Here's how you can do it:
1. Calculate the final volume of the desired solution:
To find the final volume, divide the amount of solute needed (1.60 L) by the desired concentration (3.00 M).
Final volume = amount of solute (1.60 L) ÷ desired concentration (3.00 M) = 0.5333 L or 533.3 mL.
2. Calculate the amount of stock solution needed:
The amount of stock solution needed can be calculated using the dilution equation, which states that the initial concentration multiplied by the initial volume is equal to the final concentration multiplied by the final volume.
Concentration x Volume = Concentration x Volume
Rearranging the equation, we get:
Initial volume (stock solution) = (Final concentration x Final volume) ÷ Initial concentration.
Inserting the values into the equation:
Initial volume (stock solution) = (3.00 M x 0.5333 L) ÷ 8.00 M = 0.2 L or 200 mL.
3. Prepare the solution:
Using a graduated cylinder or a volumetric flask:
a. Measure 200 mL of the 8.00 M stock solution using a measuring cylinder or pipette and transfer it to a clean container.
b. Add the measured stock solution to the volumetric flask or container.
c. Add water to the container, while swirling, until the total volume reaches 533.3 mL (or 0.5333 L). This will dilute the stock solution and create the desired 3.00 M solution.
Remember to mix the solution well to ensure that the concentration is uniform throughout. By following these steps, you can prepare the desired solution without wasting any stock solution.