A solution of ethanol water is prepared by dissolving 10ml ofethanol density 0.789g/mol in a 100ml of a solution with density 0.982g/mol.what is the cerntration of ethanol in the solution expressed in mass percent?;mass/volume percent?

mass ethanol=10*.789=7.89grams

mass solution=100*.982=98.2 grams

Mass percent= 7.89/98.2 x 100
mass volume= 7.89/100 g/ml, or7.89 %m/v
I dont know why a chem teacher is teaching mass/volume percents anymore, it is a misleading, confusing term, based solely on water dilute water solutions. This started in Biology circles, and they still use it, I think. In pharmacy, it is worse, they call it weight/volume percent, obviously not understanding the difference between weight and mass. At any rate, I do not understand why your teacher is giving this. I guess it is the same reason some still teach Esperanto....because a few folks use it.

To find the concentration of ethanol in the solution expressed in mass percent, we need to determine the mass of ethanol present in the solution.

First, let's calculate the mass of ethanol in grams:
Mass of ethanol = Volume of ethanol x Density of ethanol
Mass of ethanol = 10 ml x 0.789 g/ml
Mass of ethanol = 7.89 grams

Next, we need to calculate the mass of the entire solution:
Mass of solution = Volume of solution x Density of solution
Mass of solution = 100 ml x 0.982 g/ml
Mass of solution = 98.2 grams

Now we can determine the mass percent of ethanol in the solution:
Mass percent = (Mass of ethanol / Mass of solution) x 100
Mass percent = (7.89 grams / 98.2 grams) x 100
Mass percent = 8.03%

The concentration of ethanol in the solution expressed in mass percent is 8.03%.

To calculate the mass/volume percent, we need to consider the volume of the entire solution.

Volume percent = (Volume of ethanol / Volume of solution) x 100
Volume percent = (10 ml / 100 ml) x 100
Volume percent = 10%

The concentration of ethanol in the solution expressed in mass/volume percent is 10%.