How many grams of glycerin C3H8O3 must be dissolved in 375.9g of water at 100 degrees Celsius to reduce the pressure of water above the solution to 714.6mmHg. The solution is a non-volatile compound
Psoln = XH2O*PoH2O
Psoln = 714.6 mm
Po H2O = 760 at the boiling point of 100 C and 1 atm pressure.
Solve for XH2O and substitute into the below equation.
Then XH2O = (nH2O)/(nH2O + nglycerin)
You can calculate nH2O from the problem. Solve for n glycerin and convert to grams. Post your work if you get stuck.
Thank you DrBob222.
To find the number of grams of glycerin (C3H8O3) that must be dissolved in 375.9g of water at 100 degrees Celsius to reduce the pressure of water above the solution to 714.6mmHg, we can use Raoult's Law.
Raoult's Law states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent multiplied by the mole fraction of the solute:
P solution = X solvent * P solvent
Here, P solution is the pressure of the solution, X solvent is the mole fraction of the solvent, and P solvent is the vapor pressure of the pure solvent.
Since glycerin is a non-volatile compound, it does not contribute to the vapor pressure of the solution. Therefore, the vapor pressure of the solution will be equal to the vapor pressure of water.
Now, let's calculate the mole fraction of water in the solution:
Moles of water = mass of water / molar mass of water
Molecular mass of water (H2O) = 18.015 g/mol
Moles of water = 375.9g / 18.015 g/mol
Next, let's calculate the mole fraction of water:
Mole fraction of water = moles of water / total moles
Total moles = moles of water + moles of glycerin
Since the mass of glycerin is not given, we need additional information to calculate the moles of glycerin.
Once you have the mass of glycerin, divide it by the molar mass of glycerin to get the moles of glycerin. Then, you can calculate the total moles and the mole fraction of water.
Finally, you can use Raoult's Law to find the pressure of the solution:
P solution = X solvent * P solvent
P solution = mole fraction of water * P solvent
Given that the pressure of the solution (P solution) is 714.6mmHg, you can solve for the mole fraction of water (X solvent) and then calculate the mass of glycerin needed to achieve the desired pressure.