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182 solutions

Molarity

Q. The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood. Luminol has a molecular weight of 177 g/mol. Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00 x 10^-2 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? Express your answer with the appropriate units.

Solved • Mar 13, 2020

Molarity

Q. The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. Luminol is so sensitive that it can detect blood that has been diluted 10,000 times. A basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood. Luminol has a molecular weight of 177 g/mol. The forensic technician at a crime scene has just prepared a luminol stock solution by adding 14.0 g of luminol into a total volume of 75.0 mL of H2O. What is the molarity of the stock solution of luminol? Express your answer with the appropriate units.

Solved • Mar 13, 2020

Molarity

Q. Calculate the volume in liters of a 0.068 mol/L potassium dichromate solution that contains 100.0 g of potassium dichromate (K2Cr2O7). Be sure your answer has the correct number of significant digits.

Solved • Mar 26, 2020

Molarity

Q. A chemist adds 255.0 mL of a 1.25 mol/L potassium iodide (KI) solution to a reaction flask. Calculate the millimoles of potassium iodide the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Solved • Mar 26, 2020

Molarity

Q. A stock solution is prepared by adding 1.245 g of Mg(OH)2 to 250.0 mL of DI water. Calculate the concentration (in M) of the prepared Mg(OH)2 stock solution?

Solved • Mar 25, 2020

Molarity

Q. The molar mass of H202 is 34.0147. Stock concentration of H202 is 3.00%. Volume of stock solution of H202 used is 20.00ml. Stock concentration of KI is 1.00%. Volume of KI stock solution used is 5.00ml. 1. Calculate the initial concentration of H202 in the reaction flask after both reactants have been added. 2. Calculate the initial concentration of KI in the reaction flask after both reactants have been added.

Solved • Mar 24, 2020

Molarity

Q. Calculate the molarity of a solution prepared by dissolving 1.495 moles of LiOH in enough water to give a final volume of 750. mL. A. 1.99 M B. 1.50 M C. 1.12 M D. 0.502 M E. 0.00199 M

Solved • Mar 17, 2020