What is the molarity of a solution prepared from 15.0 grams of methanol (ch3oh, density = 0.792 g/ml) with 185.0 milliliters of ethanol (ch3ch2oh)? assume the volumes are additive.

Respuesta :

Taking into account the definition of molarity, the molarity of the solution is 2.2958 [tex]\frac{moles}{L}[/tex].

Definition of molarity

Molar concentration or molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution:

molarity= number of moles÷ volume of solution

Molarity is expressed in units [tex]\frac{moles}{L}[/tex].

This case

In this case, you have a a solution prepared from:

  • 15.0 grams of methanol (CH₃OH, density = 0.792 g/ml).
  • 185.0 milliliters of ethanol (CH₃CH₂OH)

Being the molar mass of methanol 32.04 g/mol, that is the amount of mass that the compound contains in one mole, the number of moles of methanol in the solution is calculated as:

Moles of methanol (solute) = mass ÷molar mass = 15.0 grams/ 32.04 g/mol

Moles of methanol (solute) = 0.4682 moles

On the other side, being the density of methanol 0.792 g/mL, this is  the amount of mass in a certain volume of the compound, the volume of methanol can be calculated as:

Volume of methanol = mass ÷density = 15.0 g/ 0.792 g/mL

Volume of methanol= 18.939 mL

Being the volume of ethanol 185 mL, the volume of solution can be calculated as:

Volume of solution = Volume of methanol (solute)  +  Volume of ethanol (solvent)

Volume of solution = 18.939 mL + 185 ml = 203.939 mL= 0.203939 L (being 1000 mL= 1 L)

Replacing in the definition of molarity:

molarity= 0.4682 moles÷ 0.203939 L

Solving:

molarity= 2.2958 [tex]\frac{moles}{L}[/tex]

Finally, the molarity of the solution is 2.2958 [tex]\frac{moles}{L}[/tex].

Learn more about molarity:

brainly.com/question/9324116

brainly.com/question/10608366

brainly.com/question/7429224

#SPJ1