At 20 degrees C ethanol has a density of 0.789 g/ml and H2O has a density of 1.0 g/ml. What is the % by volume of ethanol of a solution made by adding 50g of ethanol with 50g of H2O?
Tutor Answer: Use density = mass x volume to convert 50 g ethanol to volume and to convert 50.0 g H2O to volume.
%ethanol v/v = (volume ethanol/total volume?)*100 = ?
MY QUESTION:
i thought that density = m/v
i've done the math and i think you are right because based on the above formula my answer is 126.74%
However, i don't understand why if the density formula is as you stated?
2nd, is this correct?
1/50 = .02, 1/.789 = .01578
(0.01578/0.02) x 100 = 78.9%
Yes, you are right about density and no, I don't get those answers. For that density sentence I punched x instead of / button. density = mass/volume and
volume = mass/density.
50 g ethanol has v = 50/0.789 or about 60 mL (but you need to do it more accurately). Water has volume of 50/1 = 50 mL . Total 50 + 60 = 110 and percent ethanol = (volume ethanol/total volume) x 100 which is approximately 55%.
1/50 = 0.02 but
1/0.789 is not what you wrote.
Thank you for your help!
Yes, you are correct that the density of a substance is defined as mass divided by volume. So, in this case, density = mass/volume.
To calculate the % by volume of ethanol in the solution, we will use the given densities to convert the masses of ethanol and water into volumes.
For ethanol:
Density of ethanol = 0.789 g/ml
Mass of ethanol = 50g
Using the formula density = mass/volume, we can rearrange it to solve for volume:
Volume of ethanol = mass/density = 50g / 0.789 g/ml = 63.4 ml
For water:
Density of water = 1.0 g/ml
Mass of water = 50g
Volume of water = mass/density = 50g / 1.0 g/ml = 50 ml
Now, we can calculate the % by volume of ethanol in the solution:
% ethanol v/v = (volume of ethanol / total volume) x 100
Total volume = volume of ethanol + volume of water = 63.4 ml + 50 ml = 113.4 ml
% ethanol v/v = (63.4 ml / 113.4 ml) x 100 = 55.9%
Therefore, the % by volume of ethanol in the solution made by adding 50g of ethanol with 50g of water is approximately 55.9%.
You are correct that density is defined as mass divided by volume, so the formula is indeed density = m/v. However, in this case, we are given the densities of ethanol and water and we are asked to calculate the percentage by volume of ethanol in a solution.
To solve this question, we need to use the densities of ethanol and water to convert the given masses to volumes and then calculate the total volume of the solution.
First, let's convert the mass of ethanol to volume using the formula density = mass/volume. Rearranging the formula to solve for volume, we have volume = mass/density. Plugging in the values, we get volume of ethanol = 50 g / 0.789 g/mL = 63.46 mL.
Next, let's convert the mass of water to volume in the same way: volume of water = 50 g / 1.0 g/mL = 50 mL.
Now, we can calculate the percentage by volume of ethanol in the solution. The formula is %ethanol v/v = (volume of ethanol / total volume) * 100.
To find the total volume, we sum up the volumes of ethanol and water: total volume = volume of ethanol + volume of water = 63.46 mL + 50 mL = 113.46 mL.
Now, we can substitute the values into the percentage formula: %ethanol v/v = (63.46 mL / 113.46 mL) * 100 = 55.94%.
Therefore, the percentage by volume of ethanol in the solution made by adding 50 g of ethanol with 50 g of water is approximately 55.94%.
It seems that there was an error in your calculation. I hope this explanation clarifies the process for solving the problem.