one of the ingredients in detergent making, lauryl alcohol is extracted from coconut oil. A 5.00 g of this substance is added to 100 g of benzene and the solution boils at 80.78° C. what is the molar mass of lauryl alcohol?
10.5g of potassium trioxonitrate(v) salt saturated 5g of solvent at 15°c. Calculate the solubility of potassium trioxonitrate(v) salt at that same temperature in:
a) g/100g of solvents.
b)moles/ dm^3
Isaac, don't piggy back on another question. Post your own.
Note that the problem says "this substance" which leads me to believe you are adding coconut oil to the benzene. If that is the case, you can't determine the molar mass of lauryl alcohol this way. I will assume "this substance" means you are adding that many grams of lauryl which has been extracted FROM the coconut oil.
delta T = Kb*molality
delta T = 80.78-normal boiling point benzene.
Kb--look up the Kb for benzene
Solve the above delta T = Kb*m for m. Then
m = molality = mols/kg solvent.
You know kg solvent = 100 g or 0.1 kg. Usisng Kg solvent and m, solve for mols.
Then mols = grams/molar mass. You know grams and mols, solve for molar mass.
To find the molar mass of lauryl alcohol, we can use the equation:
ΔT = Kf * m
Where:
ΔT = change in boiling point (in °C)
Kf = cryoscopic constant (in °C/m)
m = molality of the solution (in mol/kg)
First, let's calculate the change in boiling point (ΔT):
ΔT = boiling point of the solution - boiling point of the solvent
The boiling point of benzene is 80.78°C, so the change in boiling point is:
ΔT = 80.78°C - 80.00°C = 0.78°C
Next, we need to calculate the molality (m) of the solution:
m = moles of lauryl alcohol / mass of benzene (in kg)
To calculate the moles of lauryl alcohol, we first need to convert the given mass of lauryl alcohol to moles. We can do this using the molar mass (M) of lauryl alcohol:
moles of lauryl alcohol = mass of lauryl alcohol / molar mass of lauryl alcohol
Now, let's calculate the moles of lauryl alcohol:
moles of lauryl alcohol = 5.00 g / molar mass of lauryl alcohol
Finally, let's calculate the molality of the solution:
m = moles of lauryl alcohol / (mass of benzene / 1000)
Now that we have the molality, we can rearrange the equation to solve for the molar mass of lauryl alcohol:
ΔT = Kf * m
m = moles of lauryl alcohol / (mass of benzene / 1000)
ΔT = Kf * (moles of lauryl alcohol / (mass of benzene / 1000))
Rearranging the equation gives us:
molar mass of lauryl alcohol = (ΔT * mass of benzene * 1000) / (Kf * moles of lauryl alcohol)
We already have all the values needed to calculate the molar mass. Make sure to substitute the appropriate values and perform the calculations to find the molar mass of lauryl alcohol.