Question

What is the concentration (m) of ch3oh in a solution prepared by dissolving 16.8 g of ch3oh in sufficient water to give exactly 230 ml of solution?

Answer 1

The Molarity concentration is expressed in units of moles / L. So let us first determine the number of moles of CH3OH, and then divide that amount by the total volume of 0.230 L of solution.

To determine the number of moles of CH3OH, divide the weight in grams of CH3OH by the molecular weight of CH3OH: (MW of CH3OH = 32 g / mol)

number of moles = 16.8 g / (32 g / mol)

number of moles = 0.525 mol CH3OH 

Then we calculate for molarity:

Molarity = 0.525 mol CH3OH / .230 L

Molarity = 2.2826 mol / L

Molarity = 2.28 M