Answer:
The glycerol solution has a molality of 2.960×10^-2 mol/kg.
Explanation:
Calculating the moles of glycerol involves the formula: Moles = Molarity × Volume of solution = 2.950×10^-2 M × 1 L = 2.950×10^-2 moles.
To find the mass of water, use: Mass = Density × Volume = 0.9982 g/mL × 998.7 mL = 996.90 g, which converts to 0.9969 kg.
The formula for molality is: Molality = Moles of solute/Mass of solvent (in kg) = 2.950×10^-2/0.9969 = 2.960×10^-2 mol/kg.
Solution:
Molality measures the concentration of a solute in a solution, defined by the amount of solute per specific mass of solvent.
Thus,
Molality = moles of solute / kg of solvent.
Therefore, kg of solvent = moles of solute / molality.
moles of solute = mass / molar mass
= 25.31 g / 101.1 g/mole
= 0.2503 mole.
kg of solvent = 0.2503 mole / 0.1982 m
= 1.263 kg
= 1263 g.
This is the final answer.
Response:
The mass percentage of a solution comprising 7.6 grams of sucrose and 83.4 grams of water equals 8.351 %.
Details:
Provided data:
Sucrose mass = 7.6 grams
Water mass = 83.4 grams
In this scenario, sucrose acts as the solute, while water is the solvent.
The calculation for mass percent of a solution is done using the following formula:
Mass percent = (Mass of Solute/Mass of Solution)(100)
As sucrose is the solute, the mass equals 7.6 grams.
The total mass of the solution, which includes both sucrose and water, comes out to:
Total mass = 7.6 grams + 83.4 grams = 91 grams
Therefore, applying the values gives mass percent = (7.6/91)(100) = 8.351 %.
At 30°C, glucose has a solubility of 1.25 g per gram of water. Given that the density of water at this temperature is 1 g/mL, the mass corresponding to 400 mL of water is also 400 g. Therefore, the concentration of the solution is calculated as 550 g divided by 400 g of water, which gives 1.375 g of glucose per gram of water. Since this concentration exceeds the solubility limit for glucose at this temperature, the solution can be classified as SATURATED.
We assume that the stated 50% is measured by volume. Molarity defines the concentration in terms of moles of solute per volume of solution.
To find the moles of NaOH, use: (0.1 moles / L)(0.4 L)
n = 0.04 moles of NaOH
Assuming we start with 1 mL of 50% NaOH solution,
(1 mL solution)(1.525 g/mL)(0.50) = 0.7625 g
Then, the number of moles calculates as follows,[
0.7625 g NaOH x (1 mol / 40 g) = 0.01906 moles of NaOH
The volume of solution required can be determined by:(0.04 moles of NaOH)(1 mL solution / 0.01906 moles of NaOH)
Thus, the needed volume comes out to be 2.09 mL
Answer: 2.09 mL
