Question

What is the concentration in molarity of an aqueous solution which contains 20.01% by mass acetonitrile (MM = 41.05 g/mol)? The density of the solution is 0.8100 g/mL.

Answer 1

To find the molarity of the solution, calculate the number of moles of acetonitrile and then divide by the volume of the solution.

Step-by-step explanation:

In order to find the molarity of the solution, we need to calculate the number of moles of acetonitrile in the solution. First, we need to determine the mass of acetonitrile in the solution:

Mass of acetonitrile = (20.01% by mass) x (mass of solution)

Next, we need to convert the mass of acetonitrile to moles:

Moles of acetonitrile = mass of acetonitrile / molar mass

Finally, we can calculate the molarity of the solution:

Molarity = moles of solute / volume of solution