The common laboratory solvent diethyl ether (ether) is often used to purify substances dissolved in it. The vapor pressure of diethyl ether , CH3CH2OCH2CH3, is 463.57 mm Hg at 25oC.
In a laboratory experiment, students synthesized a new compound and found that when 27.18 grams of the compound were dissolved in 186.3 grams of diethyl ether, the vapor pressure of the solution was 449.85 mm Hg. The compound was also found to be nonvolatile and a non-electrolyte.
What is the molecular weight of this compound ?
diethyl ether = CH3CH2OCH2CH3 = 74.12 g/mol.
This is probably a simple question but there is so much information I do not know where to start.
To find the molecular weight of the compound, you can use Raoult's law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent in the solution. In this case, the solvent is diethyl ether.
The formula for Raoult's law is:
P_solution = X_solvent * P_solvent
where P_solution is the vapor pressure of the solution, X_solvent is the mole fraction of the solvent, and P_solvent is the vapor pressure of the pure solvent.
Given that the vapor pressure of diethyl ether at 25°C is 463.57 mm Hg and the vapor pressure of the solution is 449.85 mm Hg, we can set up the following equation:
449.85 mm Hg = X_diethyl ether * 463.57 mm Hg
To find the mole fraction of diethyl ether, we need to know the mole fractions of both the solute and the solvent. In this case, the only information given is the mass of the compound (27.18 g) and the mass of diethyl ether (186.3 g).
To determine the mole fraction of diethyl ether, we first need to find the number of moles of the compound and diethyl ether using their respective masses and molecular weights. The molecular weight of diethyl ether is given as 74.12 g/mol.
Number of moles of compound = mass of compound / molecular weight of compound
Number of moles of diethyl ether = mass of diethyl ether / molecular weight of diethyl ether
Once you have both mole values, you can determine the mole fraction of diethyl ether as follows:
Mole fraction of diethyl ether = moles of diethyl ether / (moles of compound + moles of diethyl ether)
After finding the mole fraction, you can substitute this value back into the equation for Raoult's law and solve for the molecular weight of the compound.
Molecular weight of compound = (mass of compound) / (moles of compound)
By following these steps, you can find the molecular weight of the compound.