Question

A solution is made using 250.0 mL of ethanol (density 0.789 g/mL) and 499.1 mL of water (density 1.000 g/mL). What is the mass percent of the ethanol?

A. 15.8%

B. 18.5%

C. 20.2%

D. 25.0%

Answer 1

The mass percentage of ethanol in the solution can be calculated by dividing the mass of ethanol by the total mass of the solution, and then multiplying by 100. The mass percent of the ethanol in the solution is approximately 28.3%.

Step-by-step explanation:

The mass percentage of ethanol in the solution can be calculated by dividing the mass of ethanol by the total mass of the solution, and then multiplying by 100.

First, we need to calculate the mass of ethanol and water in the solution. The mass of ethanol can be found by multiplying its volume (250.0 mL) by its density (0.789 g/mL). The mass of water can be found by multiplying its volume (499.1 mL) by its density (1.000 g/mL).

The mass of ethanol is 250.0 mL x 0.789 g/mL = 197.25 g. The mass of water is 499.1 mL x 1.000 g/mL = 499.1 g.

The total mass of the solution is the sum of the mass of ethanol and the mass of water, which is 197.25 g + 499.1 g = 696.35 g.

The mass percentage of ethanol is (197.25 g / 696.35 g) x 100 = 28.3%.

Therefore, the mass percent of the ethanol in the solution is approximately 28.3%.