The forensic technician at a crime scene has just prepared a luminol stock solution by adding 15.0g of luminol into a total volume of 75.0 \rm mL of \rm H_2O.

Question

What is the molarity of the stock solution of luminol? 1.13M

Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00×10−2\it M . The diluted solution is then placed in a spray bottle for application on the desired surfaces.

How many moles of luminol are present in 2.00 L of the diluted spray? 0.120 moles

What volume of the stock solution (Part A) would contain the number of moles present in the diluted solution (Part B)?

Answer 1

mols = grams/molasr mass = about 0.08 mols, then 0.08/0.075 = about 1.13. You need to do this more accurately.

mols = M x L = 0.06 x 2L = ?

M = mols/L. You know mols and M, solve for L and convert to mL.

Answer 2

is there a formula that i am suppose to use?

Answer 3

I gave you the formulas.
First determine moles which = grams/molar mass.
Then molarity = M = mols/L soln.

The last part is
M = mols/L.