Question

40.0g of ethanol, C2H5OH, is dissolved in 150.0L of solution. Determine the molarity of ethanol in this solution.

Answer 1

The molarity of ethanol is 5.8*10⁻³ M.

Step-by-step explanation:

Molar concentration is a measure of the concentration of a solute in a solution, be it some molecular, ionic or atomic species.

Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume. It is calculated by dividing the moles of the solute by the volume of the solution:

`Molarity=(number of moles of solute)/(volume)`

Molarity is expressed in units
`(moles)/(liter)`.

Being the molar mass of ethanol 46
`(g)/(mol)`, then the number of moles that 40 grams of ethanol contain is calculated by:

`40 grams*(1 mol)/(46 grams) =0.87 moles`

So, being:

• number of moles of solute= 0.87 moles
• volume 150 L

Replacing in the definition of molarity:

`Molarity=(0.87 moles)/(150 L)`

Solving:

Molarity= 5.8*10⁻³ M

The molarity of ethanol is 5.8*10⁻³ M.