The forensic technician at a crime scene has just prepared a luminol stock solution by adding 13.0 g of luminol into a total volume of 75.0 mL of H2O. What is the molarity of the stock solution of luminol?

0.978 M

Explanation:

Given data

Mass of luminol (solute) : 13.0 g Volume of the solution = volume of water: 75.0 mL = 0.0750 L

We can find the molarity of the stock solution of luminol using the following expression.

M = mass of solute / molar mass of solute * liters of solution

M = 13.0 g / 177.16 g/mol * 0.0750 L

M = 0.978 M