Calculate the molar mass of an unknown molecular compound mixed with solid camphor C10H16O, heated and then cooled giving the following data. show all steps in calculation.
mass of unknown: 0.195 g
Tf(camphor)= 179.8 degree C
Kf(camphor)=-40.0 degree C/m
mass of camphor-25.03g
Tf(solution)=176.7 degree C
See your post below.
To calculate the molar mass of the unknown molecular compound, we need to use the freezing point depression equation and the given data. The freezing point depression equation is:
∆Tf = Kf * m
Where ∆Tf is the change in freezing point, Kf is the freezing point depression constant, and m is the molality of the solution.
First, let's calculate the change in freezing point (∆Tf):
∆Tf = Tf(camphor) - Tf(solution)
∆Tf = 179.8°C - 176.7°C
∆Tf = 3.1°C
Next, let's calculate the molality (m) of the solution:
m = (mass of unknown + mass of camphor) / (molar mass of camphor * kg of solvent)
To calculate the kg of solvent, we need to convert the mass of camphor to kg:
mass of camphor = 25.03 g = 0.02503 kg (since 1 kg = 1000 g)
Now, let's calculate m:
m = (0.195 g + 0.02503 kg) / (molar mass of camphor * 0.02503 kg)
Rearranging the equation:
(molar mass of camphor * 0.02503 kg) = (0.195 g + 0.02503 kg)
Now we have a new equation to solve for the molar mass of camphor.
molar mass of camphor = (0.195 g + 0.02503 kg) / 0.02503 kg
Substituting the values:
molar mass of camphor = (0.195 g + 0.02503 kg) / 0.02503 kg
molar mass of camphor = 0.195 g / 0.02503 kg
Now, we can use the calculated molar mass of camphor to calculate the molality (m):
m = (mass of unknown + mass of camphor) / (molar mass of camphor * 0.02503 kg)
Substituting the values:
m = (0.195 g + 0.02503 kg) / (molar mass of camphor * 0.02503 kg)
Finally, let's rearrange the freezing point depression equation to solve for the molar mass of the unknown molecular compound:
∆Tf = Kf * m
Rearranging and substituting the values:
molar mass of unknown = ∆Tf / (Kf * m)
Substituting the values:
molar mass of unknown = 3.1°C / (-40.0°C/m * m)
Now, you can solve for the molar mass of the unknown molecular compound using these calculations.