A solution of LiCl in water has XLiCl = 0.0800. What is the molality?
XLiCl = 0.08; therefore,
XH2O = 0.92
If we take 1 mol of solution, we have 0.92 mols H2O or 0.92*18 = 16.56g H2O or 0.01656 kg solvent.
m LiCl = mols LiCl/kg solvent or
0.08/0.01656 = ?
What is the molality of a solution composed of 38.0 g of cane sugar (C12H22O11) dissolved in 175 g of water?
Well, it looks like you've got some chemistry going on! Let's dive in and find the molality.
Now, to find the molality, we need to know the moles of solute and the mass of the solvent. Since you've given me the mole fraction of LiCl (XLiCl), we can use that to find the moles of LiCl.
But first, let me ask you this: Why did the chemistry teacher bring in a clown to their class? Because they heard it was good at reacting to different situations! 😄
Now, back to the problem. The moles of LiCl can be calculated using the equation:
moles of LiCl = XLiCl * moles of LiCl + XH2O * moles of H2O
But since we're given the mol fraction of LiCl (XLiCl) and we know that the mol fraction of water (XH2O) is just 1 - XLiCl, we can simplify the equation to:
moles of LiCl = XLiCl * moles of LiCl + (1 - XLiCl) * moles of H2O
Since we're dealing with a solution, we're assuming that the mass of the solvent (water) is much larger than the solute (LiCl), so the moles of H2O can be approximated by the moles of the solvent (water).
With that in mind, we can now calculate the molality using the equation:
molality = moles of solute / mass of solvent (in kg)
So, once we know the moles of LiCl, we can move on to calculating the molality. I hope this explanation has been mole-iciously entertaining! 😄
To calculate the molality (m) of a solution, we need to know the amount of solute (in moles) and the mass of the solvent (in kilograms).
Given:
- XLiCl = 0.0800
To find the amount of solute (in moles), we can start by assuming we have 100 grams of the solution. This means we have:
- Mass of LiCl = 0.0800 * 100g = 8.00g
Next, we need to convert the mass of LiCl to moles using the molar mass of LiCl:
- Molar mass of LiCl (Li = 6.94 g/mol, Cl = 35.45 g/mol) = 6.94 + 35.45 = 42.39 g/mol
- Moles of LiCl = Mass of LiCl / Molar mass of LiCl = 8.00g / 42.39 g/mol
Now, let's convert the mass of water (solvent) to kilograms. Assuming the density of water is approximately 1 g/mL, we can use the relationship:
- Mass of water = Volume of water * Density of water
Since we don't have the volume of water, we can use the fact that the solution is aqueous and assume that the density of water is close to 1 g/mL.
- Mass of water = 100g - 8.00g = 92.00g
- Mass of water in kilograms = 92.00g / 1000 = 0.092 kg
Finally, we can calculate the molality using the formula:
- m = Moles of solute / Mass of solvent (in kilograms)
- Molality (m) = Moles of LiCl / Mass of water (in kg)
Substituting the values we obtained earlier:
- Molality (m) = (8.00g / 42.39 g/mol) / 0.092 kg
Calculating the above expression will give you the molality of the solution.
To find the molality of a solution, you need to know the amount of solute (in moles) and the mass of the solvent (in kilograms). In this case, we have the mole fraction of LiCl (XLiCl), which is related to the molality (m) by the following equation:
XLiCl = (moles of LiCl) / (moles of LiCl + moles of water)
To find the molality, we need to determine the amount of water in moles. We know that the sum of the mole fractions of all components in a solution is equal to 1, so we can calculate the mole fraction of water (XH2O) as follows:
XH2O = 1 - XLiCl
Now, using the mole fraction of LiCl (XLiCl), we can set up the following equation:
XLiCl = (moles of LiCl) / (moles of LiCl + moles of water)
Solving this equation for moles of water:
(moles of LiCl + moles of water) = (moles of LiCl) / XLiCl
moles of water = (moles of LiCl) / XLiCl - moles of LiCl
Since we are given the mole fraction of LiCl (XLiCl) as 0.0800, let's assume we have 1 mole of LiCl.
moles of LiCl = 1 mole
moles of water = (1 mole) / XLiCl - (1 mole)
Lastly, to find the molality, we divide the moles of LiCl by the mass of the solvent (in this case, water) in kilograms. The molar mass of water (H2O) is approximately 18.015 g/mol.
mass of water = (moles of water) * (molar mass of water)
Now, let's calculate the molality step by step:
1. moles of LiCl = 1 mole
2. moles of water = (1 mole) / 0.0800 - (1 mole) = 11 moles
3. mass of water = (11 moles) * (18.015 g/mol) = 198.165 g
4. Convert the mass of water to kilograms: 198.165 g / 1000 g/kg = 0.198165 kg
5. molality (m) = (moles of LiCl) / (mass of water in kg) = 1 mole / 0.198165 kg
Therefore, the molality of the solution is approximately 5.04 mol/kg.