1.What is the molarity of a solution prepared by diluting 25 mL of 2.0 M HCl wit

Question

1.What is the molarity of a solution prepared by diluting 25 mL of 2.0 M HCl with enough water to make 250 mL of solution?

2.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.

A )The forensic technician at a crime scene has just prepared a luminol stock solution by adding 17.0

g of luminol into a total volume of 75.0 mL of H2O.

What is the molarity of the stock solution of luminol?

B)Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00

B)Before investigating the scene, the technician must dilute the luminol solution to a concentration of 6.00

Explanation / Answer

(1)

MV=M2V2

(2)(25)=(M2)(250)

50=250M2

.20=M2

So the Molarity of the second solution is 0.20

(2A)

M=mol/vol L

M = (17/177) / .075 L

M = 1.28 mol/L

(2B)

M=mol/vol L

6.00x10^-2 = mol / 2

0.120 = mol

(2C)

M=mol/vol L

1.28 =0.120/vol L

(1.28) (vol L) = 0.120

vol L = 0.09375 L

So around 93.75 mL

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.