Determining the Quantity of Solute by Titration A mysterious white powder is fou

Question

Determining the Quantity of Solute by Titration

A mysterious white powder is found at a crime scene. A simple chemical analysis concludes that the powder is a mixture of sugar and morphine (C17H19NO3), a weak base similar to ammonia. The crime lab takes 10.00 mg of the mysterious white powder, dissolves it in 100.00 mL water, and titrates it to the equivalence point with 2.84 mL of a standard 0.0100 M  HCl solution. What is the percentage of morphine in the white powder?

Explanation / Answer

we know that

at equivalence point

moles of base = moles of acid

also

moles = molarity x volume

so

M x V of morphine = M x V of HCl

M x 100 = 0.01 x 2.84

M = 2.84 x 10-4

now

moles = molarity x volume (L)

so

moles of morphine = 2.84 x 10-4 x 100 x 10-3

moles of morphine = 2.84 x 10-5

we know that

moles = mass / molar mass

also

molar mass of morphine is 285.34 g/ mol

so

mass of morphine = 2.84 x 10-5 x 285.34

mass of morphine = 8.1 x 10-3

now

percent of morphine = mass of morphine x 100 / mass of sample

given

mass of sample = 10 x 10-3

so

percent of morphine = 8.1 x 10-3 x 100 / 10 x 10-3

percent of morphine = 81

so

percentage of morphine in the poweder is 81%

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

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