Answer to Question #311327 in Chemistry for Viny

Question

calculate the molarity of a solution with a final volume of 500ml prepared by dissolving 25.0ml of methonal (CH3OH density =0.791ml) in choloroform

Answer 1

Solution:

Liters of CH₃OH solution = (500 mL soln) × (1L / 1000 mL) = 0.5 L soln

Density = Mass / Volume

Therefore,

Mass of CH₃OH = Density of CH₃OH × Volume of CH₃OH

Mass of CH₃OH = (0.791 g/mL) × (25.0 mL) = 19.775 g

The molar mass of methanol (CH₃OH) is 32.04 g/mol

Therefore,

Moles of CH₃OH = (19.775 g CH₃OH) × (1 mol CH₃OH / 32.04 g CH₃OH) = 0.6172 mol CH₃OH

Molarity = Moles of solute / Liters of solution

Therefore,

Molarity of CH₃OH solution = Moles of CH₃OH / Liters of CH₃OH solution

Molarity of CH₃OH solution = (0.6172 mol) / (0.5 L) = 1.2344 mol/L = 1.23 M

Molarity of CH₃OH solution = 1.23 M

Answer: The molarity of CH₃OH solution is 1.23 M