Molarity of a solution of ethanol in water

In summary, the conversation discusses how to calculate the molarity of a solution of ethanol in water, in which the mole fraction of ethanol is 0.040. It is determined that the solution is 96% water and 4% ethanol in terms of moles. There is a clarification that this does not mean the solution is 4% w/w ethanol, but rather contains 4 moles of ethanol per every 96 moles of water.
  • #1
powergirl
Calculate the molarity of a solution of ethanol in water,in which the mole fraction of ethanol is 0.040.
Can anyone help me to solve this problem?:bugeye:
 
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  • #2
i think

Then the mole fraction of water is 0.96...so the solution is 96% water and 4%Ethanol...this shoule help you going if you were unsure what the fraction was.

Molarity= Moles of Solute / litres of solution

Mole fraction (Ethanol) = Moles of Ethanol/ Moles of Ethanol + Water

So do you know how many Litres or are you just going to assume?

So if we use a basis of 100 moles...96 moles are water and 4 moles are ethanol and assume 150 litres

therefore

molarity = 4 moles /150 litres = 0.0266
 
  • #3
Thanks for helping me...:)
 
  • #4
mark-ashleigh said:
Then the mole fraction of water is 0.96...so the solution is 96% water and 4%Ethanol...

Only in terms of moles, stating it this way may sound like you are suggesting this solution is just 4% w/w ethanol - which is not true (it is 9.6% w/w).

It will be better said that such solution contains 4 moles of ethanol per every 96 moles of water.



 
  • #5
No..i said mole fraction not w/w
 
  • #6
I know what you mean though...
 

What is the definition of molarity?

Molarity, also known as concentration, is a measure of the number of moles of a solute dissolved in one liter of solution.

How is molarity calculated?

Molarity is calculated by dividing the number of moles of solute by the volume of the solution in liters.

How does the molarity of a solution change with temperature?

The molarity of a solution can change with temperature because the volume of the solution can change with temperature, but the number of moles of solute remains constant. Therefore, as the temperature increases, the molarity decreases, and vice versa.

What is the molarity of a solution of ethanol in water?

The molarity of a solution of ethanol in water can vary depending on the concentration of ethanol and the volume of the solution. However, a commonly used concentration is 95% ethanol, which has a molarity of approximately 28.3 M.

How is the molarity of a solution affected by dilution?

When a solution is diluted, the volume of the solution increases while the number of moles of solute remains constant. Therefore, the molarity decreases with dilution.

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