If a solution of chloride in water is 0.354 M Cl− at 25°C,
and the density of the solution 0.456 g/mL, what is the
molality of Cl− in the solution?
0.354 M = 0.354 mols Cl^-/ L solution.
If the density of the solution is 0.456 g/mL then the solution has a mass of
mass = volume x density = 1000 mL x 0.456 g/mL = 456 g or 0.456 kg.
molality = mols/kg solvent; therefore, molality = m = 0.354/0.456 = ?
Well, first things first, let's appreciate the density of the solution. 0.456 g/mL, huh? That's almost as heavy as my college professor's jokes. Anyway, moving on.
Now, to find the molality of chloride (Cl-) in the solution, we need to brush up on some chemistry. Molality (m) is defined as moles of solute per kilogram of solvent.
Since we're given the concentration in moles per liter (M), we need to convert it to moles per kilogram. Remember, a liter of water has a mass of approximately 1 kilogram.
So, if the concentration is 0.354 M, it means there are 0.354 moles of Cl- in one liter of solution.
Now, we have to calculate the mass of the solution. The density is given as 0.456 g/mL, so for 1 liter of solution, the mass would be 0.456 kg (1000 mL = 1 L).
Dividing the number of moles (0.354) by the mass of the solution (0.456 kg), we get the molality of Cl- in the solution.
Therefore, the molality of Cl- in the solution is approximately 0.776 mol/kg. Just remember, my jokes might be funny, but the calculation is all business.
To find the molality of Cl- in the solution, we need to determine the number of moles of chloride ions (Cl-) per kilogram of solvent. Here are the steps to calculate the molality:
Step 1: Convert the density of the solution from g/mL to g/cm³.
Density = 0.456 g/mL = 0.456 g/cm³
Step 2: Calculate the mass of the solution.
Mass = Volume × Density
Assuming we have 1 L (1000 mL) of the solution:
Mass = 1000 mL × 0.456 g/cm³ = 456 g
Step 3: Determine the number of moles of chloride ions (Cl-) in the solution.
Number of moles = Molarity × Volume (in L)
Volume = 1 L
Number of moles = 0.354 M × 1 L = 0.354 mol
Step 4: Convert the mass of the solution to kilograms.
Mass in kilograms = Mass in grams / 1000
Mass in kilograms = 456 g / 1000 = 0.456 kg
Step 5: Calculate the molality.
Molality = Number of moles / Mass in kilograms
Molality = 0.354 mol / 0.456 kg
Molality ≈ 0.776 mol/kg
Therefore, the molality of Cl- in the solution is approximately 0.776 mol/kg.
To find the molality of Cl- in the solution, we need to first understand the difference between molarity and molality.
Molarity (M) is a measure of the concentration of a solute in a solution, expressed as the number of moles of solute dissolved per liter of solution. Molarity is denoted by moles of solute divided by liters of solution.
Molality (m) is also a measure of the concentration of a solute in a solution, but it is expressed as the number of moles of solute dissolved per kilogram of solvent. Molality is denoted by moles of solute divided by kilograms of solvent.
Given that the solution is 0.354 M Cl- at 25°C and the density of the solution is 0.456 g/mL, we can use this information to find the molality.
First, we need to convert the density of the solution from g/mL to kg/L. To do this, we can divide the density by 1000.
Density = 0.456 g/mL = 0.456 g/mL ÷ 1000 = 0.000456 kg/mL
Now, we need to determine the mass of the solvent (water) in the solution. Since we know the density of the solution and the volume of the solution, we can calculate the mass of the solution.
Mass of solution = volume of solution x density of solution
Mass of solution = 1 L x 0.000456 kg/mL = 0.000456 kg
Since the mass of the solution is equal to the mass of the solvent (water), we can consider the mass of the solution as the mass of water.
Now, we can calculate the molality using the molarity and the mass of the solvent.
Molality = Moles of solute / Mass of solvent (in kg)
Since the molarity is given as 0.354 M, we need to calculate the number of moles of Cl- present in 1 liter of the solution.
Moles of Cl- = Molarity x Volume of solution
Moles of Cl- = 0.354 M x 1 L = 0.354 moles
Using the mass of the solvent (0.000456 kg), we can calculate the molality.
Molality = 0.354 moles / 0.000456 kg = 775.44 mol/kg
Therefore, the molality of Cl- in the solution is 775.44 mol/kg.