Respuesta :
First, we determine the mass of stearic acid in the solution by multiplying the given concentration by the volume.
mass of stearic acid = (5.4 x 10^-4 g/L) (0.25 mL) (1000 mL/1L)
= 0.135 g
Then, we divide this amount by the molar mass in order to obtain the number of moles of stearic acid. The molar mass of stearic acid is 284.4772 g/mol.
moles stearic acid = 0.135 g / (284.4772 g/mol)
= 4.75 x 10^-4 mol
mass of stearic acid = (5.4 x 10^-4 g/L) (0.25 mL) (1000 mL/1L)
= 0.135 g
Then, we divide this amount by the molar mass in order to obtain the number of moles of stearic acid. The molar mass of stearic acid is 284.4772 g/mol.
moles stearic acid = 0.135 g / (284.4772 g/mol)
= 4.75 x 10^-4 mol
Explanation:
The given data is as follows.
Volume = 0.25 ml = [tex]0.25 \times 0.001 L/ml[/tex] = 0.00025 l
mass = [tex]5.4 \times 10^{-4} g/l[/tex]
Also, it is known that molar mass of stearic acid is 284.48 g/mol.
Therefore, calculate the mass present in 0.00025 l as follows.
[tex]0.00025 l \times 5.4 \times 10^{-4} g/l[/tex]
= [tex]0.00135 \times 10^{-4}[/tex]
= 13.5 g
As number of moles is mass divided by molar mass of the substance. Hence, calculate the number of moles of stearic acid as follows.
No. of moles = [tex]\frac{mass}{\text{molar mass}}[/tex]
= [tex]\frac{13.5 g}{284.48 g/mol}[/tex]
= 0.047 mol
Thus, we can conclude that there are 0.047 mol of steric acid are contained in the given solution.
