chemistry

posted by .

a 250.0 ml sample of an aqueous solution at 25 degrees celsius contains 35.8 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 11.25 mmHg, what is the molar mass of the unknown compound?

I know you need to have the answer in g/mol. I have grams (0.358 g), but am having a hard time figuring out how to find mols.

  • chemistry -

    pi = MRT. Substitute and solve for M = molarity. Then n = grams/molar mass. You know grams and mols, solve for molar mass. Note that pressure should be in atm for M to be molarity.

  • chemistry -

    So you invert the equation to M=pi/RTi to solve for Molarity. I plug in the numbers ((0.1480 atm)/(0.08206 L atm/K mol)(298K) (1))
    That equals 6.1554*10^-4 mols.

    Dont you divide 0.358g/6.1554*10^-4??

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    The new vapor pressure of a solution of 3.25g of an unknown compound in 22.35g of H2O is 114.9mmHg at 55 degrees Celcius. What is the molar mass of the unknown compound?
  2. chemistry

    an aqueous solution containing 17.5g of an unknown molecular(nonelectrolyte) compound in 100.0g of water has a freezing point of 1.8 degress C. calculate the molar mass of the unknown compound
  3. Chemistry

    A dilute aqueous solution of an organic compound soluble in water is formed by dissolving 2.35 g of the compound in water to form 0.250 L solution. The resulting solution has an osmotic pressure of 0.605 atm at 25 Celsius. Assuming …
  4. chemistry

    A 250.0 mL sample of an aqueous solution at 25 degrees Celsius contains 35.8 mg of an unknown nonelectrolyte compound. If the solution has an osmotic pressure of 11.25 mmHg, what is the molar mass of the unknown compound?
  5. chemistry

    2. When 0.354 g of an unknown nonelectrolyte compound was dissolved in 12.5 g of benzene a solution was formed that froze at 4.46°C. (a) Calculate the molar mass of the unknown compound. The freezing point of benzene is 5.48°C, and …
  6. chemistry

    2. When 0.354 g of an unknown nonelectrolyte compound was dissolved in 12.5 g of benzene a solution was formed that froze at 4.46°C. (a) Calculate the molar mass of the unknown compound. The freezing point of benzene is 5.48°C, and …
  7. Chemistry

    When 0.354 g of an unknown nonelectrolyte compound was dissolved in 12.5 g of benzene a solution was formed that froze at 4.46 degrees C. Calculate the molar mass of the unknown compound. The freezing point of benzene if 5.48 degrees …
  8. Chemistry

    An aqueous solution containing 17.1 g of an unknown molecular compound ( nonelectrolyte) in 105.0g of water was found to have a freezing point of -1.8 degrees Celsius. What is the molar mass of the unknown compound?
  9. chemistry

    1.00 of an aqueous solution contains 1.52g of a compound used in antifreeze. If the osmotic pressure of this solution at 20.0 degree C is 448 torr, calculate the molar mass of the antifreeze compound
  10. Chemistry

    An unknown compound contains only carbon, hydrogen, and oxygen. Combustion analysis of the compound gives mass percents of 31.57% Carbon and 5.30% H. The molar mass is determined by measuring the freezing-point depression of an aqueous …

More Similar Questions