An aqueous KNO3 solution is made using 72.5 grams of KNO3 diluted to a total solution volume of 2.00 liters. If the molarity of the solution is .359 M and the molality of the solution is .354, what is the mass percent of the solution?

M = moles/L soln

moles KNO3 = grams KNO3/molar mass = 72.5/101.1/2L soln = 0.359 to confirm the 0.359 stated in the problem.

m = mols/kg solven
0.7171/kg solvent. We must calculate the kg solvent.
0.354 = 0.7171/kg solvent and
kg solvent = 0.7171/0.354 = about 2.026 kg. (Confirm: 0.7171/2.026kg = 0.354.

The total mass of the solution, therefore, is 72.5 g + 2,026 g = 2098.5.
%soln w/w = (g KNO3/total mass)*100 =?

m = moles/kg solvent

To find the mass percent of a solution, you need to calculate the mass of the solute (KNO3) and the mass of the solution (KNO3 + water).

Let's begin by calculating the mass of the solute (KNO3). Given that 72.5 grams of KNO3 were used to make the solution, this is the mass of the solute.

Next, we need to calculate the mass of the solution. The solution consists of the solute (KNO3) and the solvent (water). Since the solution is made by diluting 72.5 grams of KNO3 to a total solution volume of 2.00 liters, we assume the volume of water added is 2.00 L - 0 L (as KNO3 is fully soluble in water) = 2.00 L.

Now we need to convert the molality of the solution to moles of KNO3 per kilogram of solvent. The molality (m) is defined as the moles of solute per kilogram of solvent. Given that the molality of the solution is 0.354 mol/kg, this means there are 0.354 moles of KNO3 in 1 kilogram of water. We don't know the mass of the water, but we can assume it is nearly equal to 2.00 kg (since the density of water is approximately 1 g/mL).

Using the molality and mass assumptions, we can calculate the moles of KNO3 in the solution. Moles = Molality x Mass(kg) = 0.354 mol/kg x 2.00 kg = 0.708 moles.

Now we have the mass of the solute (KNO3), which is 72.5 grams, and the moles of KNO3 in the solution, which is 0.708 moles. We can find the molar mass of KNO3 by summing the atomic masses of its components: K (39.10 g/mol) + N (14.01 g/mol) + 3 O (16.00 g/mol) = 101.11 g/mol.

Using the molar mass, we can find the mass of the solution by multiplying the moles of KNO3 by the molar mass: Mass = Moles x Molar Mass = 0.708 moles x 101.11 g/mol = 71.64 grams.

Finally, to calculate the mass percent of the solution, we divide the mass of the solute by the mass of the solution and multiply by 100: Mass Percent = (Mass of Solute / Mass of Solution) x 100 = (72.5 g / 71.64 g) x 100 = 101.19%.

Therefore, the mass percent of the solution is approximately 101.19%.

To find the mass percent of the solution, we need to calculate the mass of the solution and then find the mass percent using the formula:

Mass Percent = (Mass of solute / Mass of solution) x 100

First, let's calculate the mass of the solution. The mass of the solution is the sum of the mass of the solute (KNO3) and the mass of the solvent (water).

Given:
Mass of KNO3 = 72.5 grams
Volume of solution = 2.00 liters

The molarity of the solution (M) is given by the formula:
Molarity = (moles of solute / volume of solution in liters)

We are given the molarity (M) as 0.359 M, and the volume of the solution is 2.00 liters. So, we can rearrange the formula to find the moles of solute (KNO3) in the solution:

moles of solute (KNO3) = Molarity x volume of solution

moles of solute (KNO3) = 0.359 M x 2.00 L
moles of solute (KNO3) = 0.718 moles

Now, let's calculate the mass percent of the solution using the formula mentioned earlier:

Mass Percent = (Mass of solute / Mass of solution) x 100

Mass of solute (KNO3) = 72.5 grams
Mass of solution = Mass of solute (KNO3) + Mass of solvent (water)

We can calculate the mass of the solvent (water) by using the molality (m) of the solution. The molality is defined as the number of moles of solute per kilogram of solvent.

Given:
Molality (m) = 0.354
Moles of solute (KNO3) = 0.718 moles

Molality = (moles of solute / mass of solvent in kilograms)

We can rearrange the formula to find the mass of the solvent (water):

mass of solvent (water) = (moles of solute / molality)

mass of solvent (water) = 0.718 moles / 0.354
mass of solvent (water) = 2.030 kg

Now, let's calculate the mass of the solution:

Mass of solution = Mass of solute (KNO3) + Mass of solvent (water)

Mass of solution = 72.5 grams + (2.030 kg x 1000 grams/kg)
Mass of solution = 2072.5 grams

Finally, let's calculate the mass percent of the solution:

Mass Percent = (Mass of solute / Mass of solution) x 100

Mass Percent = (72.5 grams / 2072.5 grams) x 100
Mass Percent = 3.5%

Therefore, the mass percent of the solution is 3.5%.