Find the mass of urea needed to prepare 50.1 of a solution in water in which the mole fraction of urea is 7.50×10−2.
50.1 what?
grams.
Let x = mass urea.
n urea = x/60.06
n H2O = 50.1-(x/18)
n urea = [n urea/(n urea + n H2O)]
So (x/60)/[x/60)+{50.1-x}/18] = 0.075 and solve for x.
If I didn't make a math error the answer is approximately 10 g.
where did you get 60.06 from?
oh, molar mass, duh. got it
To find the mass of urea needed to prepare a given solution, we need to use the concept of mole fraction. Mole fraction is the ratio of the moles of a component to the total moles of all components in a solution.
Given:
Mole fraction of urea (X urea) = 7.50×10^−2
Total volume of solution (V) = 50.1 L
To find the mass of urea, we need to perform the following steps:
Step 1: Convert the mole fraction to moles.
To calculate the moles of urea (n urea), we can use the equation:
n urea = X urea * n total
Since the mole fraction is given, we need to find the total moles of all components (n total) first.
Step 2: Calculate the total moles of all components (n total).
The mole fraction of urea is equal to the moles of urea divided by the total moles (n urea / n total). So, we can rearrange the equation as follows:
n total = n urea / X urea
Step 3: Convert the moles to mass.
The molar mass of urea (M urea) is required to convert moles to mass, and it is equal to 60.06 g/mol.
To calculate the mass, we can use the equation:
Mass = n urea * M urea
Now, let's plug in the given values:
Step 1: Convert the mole fraction to moles.
n urea = 7.50×10^−2 * n total
Step 2: Calculate the total moles of all components.
n total = n urea / X urea
Step 3: Convert the moles to mass.
Mass = n urea * M urea
Using these equations, we can find the mass of urea needed to prepare the solution.