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

User Brethlosze
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1 Answer

6 votes

Answer:

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.

User Orkhan Alizade
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