What is the mass percent of ethanol in a liquor that is 43.0% ethanol by volume?
The mass percent of ethanol in the described liquor is approximately 37.4%. This is calculated by converting the volume of ethanol to mass using the given density, doing the same for water, and then getting a percentage from the mass of ethanol over the total mass of the solution.
Understanding Concentration of Ethanol in Mass Percent
Mass percent is a measurement of the concentration of a solute in a solution, expressed as the percentage of the mass of the solute to the total mass of the solution. In this case, we are determining the mass percent of ethanol in a liquor that is 43.0% ethanol by volume.
To calculate the mass percent, we need to convert the volume of ethanol to mass and then calculate the percentage of ethanol in the total solution. The density of ethanol is 0.789 g/mL, while the density of water is 0.998 g/mL. We can assume that the volumes are additive, meaning the total volume of the solution is the sum of the volumes of ethanol and water.
Firstly, for every 100 mL of the solution that is 43.0% ethanol by volume, we have 43 mL of ethanol. Multiplying this volume by the density of ethanol (0.789 g/mL) gives us 33.927 g of ethanol in the solution.
To find the mass of water in the solution, we subtract the volume of ethanol from the total volume. If we assume 100 mL of the solution for simplicity, this would leave us with 57 mL of water. Multiplying the volume of water by the density of water (0.998 g/mL) gives us approximately 56.886 g of water in the solution.
Adding the mass of ethanol and the mass of water together gives the total mass of the solution, which is 33.927 g + 56.886 g = 90.813 g.
Finally, to calculate the mass percent of ethanol in the solution, we divide the mass of ethanol (33.927 g) by the total mass of the solution (90.813 g) and multiply by 100%. This gives us a mass percent of approximately 37.4% ethanol in the described liquor.
In conclusion, the concentration of ethanol in mass percent in the liquor described is roughly 37.4%. This calculation is based on converting the volumes of ethanol and water to masses using their respective densities and then determining the percentage of ethanol in the total solution mass.