I need help geting started i did come up with anwser not correct, but i just need some instruction on how to begin the process. The forensic technician at a crime scene has just prepared a luminol stock solution by adding 17.0g of luminol into a total volume of 75.0 mL of H2O.
What is the molarity of the stock solution of luminol? (Luminol has a molecular weight of 177 g/mol).

Question

aaronq · Answer

use the molarity formula $M=\dfrac{n_{solute}}{L_{solution}}$

$n=\dfrac{m}{MW}$

so you can just plug one into the other to simplify things (or you can find moles first, then plug into the molarity formula).

$M=\dfrac{\dfrac{m}{MW}}{L_{solution}}=\dfrac{m}{MW*L_{solution}}$

anonymous · Answer

i converted 75ml$$convert 75ml \to l = .075l h20, then convert 17.0 g luminol \to mol =.096mol luminol , then plug , the formula$$ but i did something wrong should i do something with h20

aaronq · Answer

no thats fine, divide the moles by the liters now to find the molarity