The Correct Answer and Explanation is:
The correct answer is C. 0.761 g/mL.
To determine the concentration in grams of solute per milliliter of solvent, we need to follow a clear formula: Concentration = Mass of solute / Volume of solvent. The problem provides us with the necessary values to find the solution.
First, we identify the mass of the solute. The problem states this directly as 0.086 grams. This value will be the numerator in our calculation.
Next, we need to find the volume of the solvent in milliliters. The problem gives us the mass of the water that was evaporated, which is 0.113 grams. This evaporated water was the solvent in the original solution. The question requires the volume of the solvent, not its mass. To convert the mass of water to volume, we use the provided density information: 1 gram of water is equivalent to 1 milliliter of water. Therefore, a mass of 0.113 grams of water has a volume of 0.113 milliliters. This value will be the denominator in our calculation. The temperature of 30.1 °C is extra information and is not needed for this specific calculation.
Now, we can plug these values into the concentration formula:
Concentration = (Mass of solute) / (Volume of solvent)
Concentration = 0.086 g / 0.113 mL
Performing the division gives us the final concentration:
0.086 ÷ 0.113 ≈ 0.76106 g/mL
When we round this result to three significant figures, consistent with the provided options, we get 0.761 g/mL. This matches option C, making it the correct answer. The other options are incorrect because they misuse the given data; for example, option A uses only the solute mass and option D uses only the solvent’s numerical value.
