Given dry, powdered Evans Blue, how would you prepare 100 mL of a 500 mg/L stock solution using water as the diluent?

I would appreciate any help, even just getting started. Thanks!

How many mg do you want? That's

0.100 L x 500 mg/L = 50 mg.
So weigh out 50 mg, place in a 100 mL volumetric flask, dissolve in a little water and make to the mark. Mix. Not so hard. eh?

To prepare a 500 mg/L stock solution of Evans Blue using the dry, powdered form, you would need to follow a few steps. Here's how you can get started:

Step 1: Determine the amount of Evans Blue powder required
First, you need to figure out how much of the powdered Evans Blue is needed to make the desired concentration. In this case, you want a 500 mg/L concentration in a final volume of 100 mL.

The formula to calculate the amount of solute needed is:

Mass = Concentration × Volume

Rearranging the formula, you get:

Mass = Concentration × Volume

Now plug in the values:

Mass = (500 mg/L) × (100 mL)

Mass = 50,000 mg

So, you will need 50,000 mg (or 50 grams) of dry, powdered Evans Blue.

Step 2: Prepare the stock solution
Once you know the amount of powder required, the next step is to dissolve it in water to make the stock solution.

To do this, follow these steps:
1. Weigh 50 grams of dry, powdered Evans Blue.
2. Add the weighed powder to a container (such as a beaker or a flask).
3. Measure 100 mL of water using a graduated cylinder.
4. Slowly add the measured water to the container with the powdered Evans Blue.
5. Stir or shake the container vigorously until the powder is completely dissolved.

After completing these steps, you will have prepared a 100 mL stock solution with a concentration of 500 mg/L. Remember to label the container properly, indicating the concentration and contents.