Question

A throat spray is 1.40% by mass phenol, C₆H₅OH, in water. If the solution has a density of 0.9956 g/mL, calculate the molarity of the solution.

a) 0.042 M
b) 0.070 M
c) 0.140 M
d) 0.280 M

Answer 1

To calculate the molarity of the throat spray solution, divide the number of moles of phenol by the volume of the solution in liters. The molarity of the solution is 0.149 M.

Step-by-step explanation:

To calculate the molarity of the throat spray solution, we first need to calculate the number of moles of phenol present in the solution. We can then divide this by the volume of the solution in liters to get the molarity.

Given that the throat spray is 1.40% phenol by mass and has a density of 0.9956 g/mL, we can assume that 100 mL of the solution has a mass of 1.40 g of phenol.

Using the molar mass of phenol (C6H5OH) of 94.11 g/mol, we can calculate the number of moles of phenol as follows:

moles = mass / molar mass = 1.40 g / 94.11 g/mol = 0.0149 mol

Finally, we can calculate the molarity of the solution by dividing the number of moles of phenol by the volume of the solution in liters:

molarity = moles / volume = 0.0149 mol / 0.1 L = 0.149 M