The forensic technician at a crime scene has just prepared a luminol stock solution by adding 11.0 g 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.
To find the molarity of the stock solution, we need to calculate the number of moles of luminol in the solution and then divide it by the volume in liters.
Step-by-step calculation:
1. Convert the mass of luminol to moles:
Molar mass of luminol = 177 g/mol
Moles of luminol = Mass (g) / Molar mass (g/mol)
Moles of luminol = 11.0 g / 177 g/mol
2. Calculate the volume of the solution in liters:
Volume of the solution = 75.0 mL = 75.0 mL * (1 L / 1000 mL)
3. Calculate the molarity:
Molarity (M) = Moles of solute / Volume of solution (L)
Molarity = Moles of luminol / Volume of solution
Now, let's plug in the values and calculate the molarity of the stock solution:
Moles of luminol = 11.0 g / 177 g/mol = 0.0621 mol
Volume of solution = 75.0 mL * (1 L / 1000 mL) = 0.075 L
Molarity = 0.0621 mol / 0.075 L
Molarity = 0.828 M (rounded to three decimal places)
Therefore, the molarity of the stock solution of luminol is approximately 0.828 M.
mols luminol = grams/molar mass = ?
Then M = mols/L solution.