Question

in words, describe how you would prepare 250 ml of 2.10 m magnesium chloride solution if you have the pure solute available to you. Show all necessary calculations.

Answer 1

I assume you know how to do this. If not let me know.

Answer 2

I do not understand how to do this question, no.

Answer 3

But you knew how to calculate the 4.5 M problem and dilute the 14.1 M stock solution. This is a far simpler problem. Again, I assume that is 2.10 M and 2.10 m solution.
You want a 2.10 M solution of MgCl2. M = mols/L solution. You want 500 mL.
How many moles do you want? That's mols = M x L = 2.10 x 0.500 = ?
How many grams is that? grams = mols MgCl2 x molar mass MgCl2 = ?
So you weigh out that many grams MgCl2, transfer the solid (I always tell my students to transfer QUANTITATIVELY) to the 500 mL volumetric flask, add some water, swirl until the solid has dissolved, make to the mark on the flask with distilled (or deionized) water, stopper, mix thoroughly, label. Done.