The concentration of lead nitrate (Pb(NO3 )2 ) in a 0.726 M solution is __________ molal. The density of the solution is 1.202

g/mL.

thanks i was able to solve it...

To find the molality of a solution, we need to know the moles of solute and the mass of the solvent.

Moles of solute (lead nitrate, Pb(NO3)2):
First, we need to calculate the moles of lead nitrate present in the solution.
Molarity (M) is defined as moles of solute per liter of solution.
Given: Molarity (M) = 0.726 M
Volume of solution = 1 L (as we are given the concentration in terms of liters)

Therefore, the moles of lead nitrate in the solution is given by:
Moles of Pb(NO3)2 = Molarity × Volume
= 0.726 mol/L × 1 L
= 0.726 mol

Mass of solvent (water):
The mass of the solvent can be calculated using the density of the solution and its volume.

Given: Density = 1.202 g/mL
Volume of solution = 1 L

Therefore, the mass of the solution is given by:
Mass of solution = Density × Volume
= 1.202 g/mL × 1000 mL
= 1202 g

Since the density is given for the solution, we need to assume that the density is essentially the same as the density of the solvent (water). Therefore, the mass of the solvent is also 1202 g.

Now, we can calculate the molality (m) of the solution:
Molality (m) is defined as moles of solute per kilogram of solvent.

Molality (m) = Moles of solute ÷ Mass of solvent (in kg)
= 0.726 mol ÷ 1.202 kg
≈ 0.604 mol/kg

Therefore, the concentration of lead nitrate in the 0.726 M solution is approximately 0.604 molal.

To calculate the molality (molal concentration) of a solution, we need to know the moles of solute and the mass of the solvent.

In this case, the solute is lead nitrate (Pb(NO3)2), and the solvent is the solution itself. The given concentration is in molarity (M), which tells us the moles of solute per liter of solution.

To find the moles of solute, we multiply the molarity by the volume of the solution in liters:

Moles of solute (Pb(NO3)2) = molarity (M) × volume of solution (L)

Given:
Molarity (M) = 0.726 M

However, we don't have the volume of the solution in liters. Instead, we are given the density of the solution, which can help us find the volume.

Density (ρ) = mass (g) / volume (mL)

To find the volume in liters, we rearrange the equation:

Volume (L) = mass (g) / density (g/mL)

Given:
Density (ρ) = 1.202 g/mL

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

Volume (L) = mass (g) / density (g/mL)
Volume (L) = 1 mL / 1.202 g/mL

The volume of the solution is 0.830 L.

Finally, we can calculate the moles of solute:

Moles of solute (Pb(NO3)2) = molarity (M) × volume of solution (L)
Moles of solute (Pb(NO3)2) = 0.726 M × 0.830 L

The moles of Pb(NO3)2 in the solution are 0.60268 mol.

To calculate the molality (molal concentration), we need to know the mass of the solvent. However, the mass of the solvent is not provided in the question. If you have the mass of the solvent, divide the moles of solute by the mass of the solvent in kilograms:

Molality (molal concentration) = moles of solute / mass of solvent (kg)

Please provide the mass of the solvent (in kg) to determine the molality of the solution.

M = moles/L

0.726 means 0.726 moles/L.
mass = volume x density
mass = 1000 mL x 1.202 g/mL = 1202 grams.
Convert 0.726 moles to grams and subtract that from 1202 g to find grams solvent then convert to kg solvent.
Finally, m = moles/kg solvent.