Morphine has the formula C₁₇H₁₉NO₃. It is a base and accepts one proton per molecule. It is isolated from opium. A 0.682-g sample of opium is found to require 8.92 mL of a 0.0116 M solution of sulfuric acid for neutralization. Assuming that morphine is the only acid or base present in opium, calculate the percent morphine in the sample of opium.

Verified step by step guidance

1. Determine the number of moles of sulfuric acid (H2SO4) used in the neutralization. Use the formula: moles = molarity (M) imes volume (L). Remember to convert the volume from mL to L by dividing by 1000.
2. Since morphine accepts one proton per molecule, the number of moles of morphine will be equal to the number of moles of H2SO4 used.
3. Calculate the molar mass of morphine (C17H19NO3). Add the atomic masses of carbon (C), hydrogen (H), nitrogen (N), and oxygen (O) according to the number of each atom in the formula.
4. Determine the mass of morphine in the sample by multiplying the number of moles of morphine by its molar mass.
5. Calculate the percent of morphine in the opium sample by using the formula: (mass of morphine / mass of opium sample) imes 100.

Key Concepts

Acid-Base Neutralization

Acid-base neutralization is a chemical reaction where an acid reacts with a base to produce water and a salt. In this context, sulfuric acid (H2SO4) reacts with morphine, which acts as a base, accepting protons. The stoichiometry of the reaction is crucial for determining the amount of morphine present in the opium sample based on the volume and concentration of the acid used.

Molarity and Moles

Molarity (M) is a measure of concentration defined as moles of solute per liter of solution. To find the number of moles of sulfuric acid used in the neutralization, the molarity and volume of the acid solution must be converted into moles using the formula: moles = Molarity × Volume (in liters). This calculation is essential for determining how many moles of morphine were neutralized by the acid.

Percent Composition

Percent composition is a way to express the concentration of a specific component in a mixture, calculated as the mass of the component divided by the total mass of the mixture, multiplied by 100. In this problem, once the moles of morphine are determined, the mass can be calculated and then used to find the percent composition of morphine in the opium sample, providing insight into its purity.