The forensic technician at a crime scene has just prepared a luminol stock solution by adding 10.0 g of luminol into a total volume of 75.0 mL of H2O . What is the molarity of the stock solution of luminol

0.753M

Explanation:

Molecular formula of luminol is as follows: C8H7N3O2

Molecular formula of the luminol (C8H7N3O2) = 12(8) + 1(7) + 14(3) + 16(2)

= 96 + 7 + 42 + 32

= 177g/mol

mole of luminol = mass/molar mass

mole = 10 ÷ 177

mole = 0.0565 mol

Molarity can be calculated using the formula: Molarity = mol/volume (L)

Volume of water = 75.0 mL = 75/1000

= 0.075L

Molarity (M) = 0.0565 ÷ 0.075

The molarity of the stock solution = 0.753M