A solution of LiCl in water is 18.0 wt% LiCl. What is the mole fraction of LiCl?
18% LiCl means 18 g LiCl/(18 g LiCl+ 82 g H2O)
moles LiCl = 18 g/molar mass.
moles H2O = 82 g/molar mass.
XLiCl = moles LiCl/total moles.
mmm so i did Licl molar mass is 42.394
18/42.394=.425 moles of LiCl
then water is 18.0152
82/18.0152=4.55 moles of H2O
so .425+4.55=4.98
(.425)/(4.98)=.0853 <---mole fraction of LiCl
ok so is this right now?
ok i did that and got 0.0933 is this correct?
Yes, XLiCl = 0.085
Ah, the delightful world of mole fractions! I hope you brought your clown nose for this one. Now, to calculate the mole fraction of LiCl in this solution, we need a little chemistry magic.
First, let's convert the weight percent into grams. Assuming we have 100 grams of the solution, 18 grams will be LiCl.
Now, we need to determine the moles of LiCl. The molar mass of LiCl is approximately 42.39 g/mol (6.94 g/mol for Li and 35.45 g/mol for Cl). So, 18 grams of LiCl is roughly 0.425 moles.
Since we know that the total weight of the solution is 100 grams and the weight of LiCl is 18 grams, the weight of water in the solution can be calculated as 82 grams.
The molar mass of water (H2O) is approximately 18.02 g/mol. To find the moles of water, we do 82 grams divided by 18.02 g/mol, giving us approximately 4.55 moles.
Now, let's add the moles of LiCl and water together. We have 0.425 moles of LiCl and 4.55 moles of water, totaling approximately 4.975 moles.
Finally, the mole fraction of LiCl is given by dividing the moles of LiCl by the total moles of both solute and solvent. So, 0.425 moles of LiCl divided by 4.975 moles gives us an approximate mole fraction of 0.0854.
So, the mole fraction of LiCl in this solution is around 0.0854. Voila!
To find the mole fraction of LiCl in a solutions, you first need to determine the number of moles of LiCl present in the solution.
Step 1: Convert the weight percentage to grams
Since the solution is 18.0 wt% LiCl, it means that 18.0 grams of LiCl is present in every 100 grams of the solution.
Step 2: Calculate the number of moles of LiCl
To calculate the number of moles, you need the molar mass of LiCl, which is the sum of the atomic masses of lithium (Li) and chloride (Cl). Li has an atomic mass of 6.94 g/mol, and Cl has an atomic mass of 35.45 g/mol.
Molar mass of LiCl = (6.94 g/mol) + (35.45 g/mol) = 42.39 g/mol
Now, you can calculate the number of moles of LiCl using the formula:
moles = mass / molar mass
moles = 18.0 g / 42.39 g/mol
Step 3: Convert the moles of LiCl to the mole fraction
The mole fraction (X) is calculated by dividing the moles of a particular component by the total moles of all components in the solution.
Since the solution consists only of LiCl and water, the mole fraction of LiCl can be calculated as:
X(LiCl) = moles of LiCl / (moles of LiCl + moles of water)
Note that the number of moles of water can be calculated by dividing the mass of water by its molar mass, assuming its density is 1 g/mL.
Now, you have the moles of LiCl, and you can calculate the mole fraction.