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?

  1. 👍 0
  2. 👎 0
  3. 👁 90
asked by regina
  1. Note the correct spelling of celsius.

    Psoln = XH2O*Pnormal
    Substitute for Psoln 114.9, look up vapor pressure of H2O at 55 C and substitute for Pnormal, solve for XH2O.

    Then
    moles H2O/(moles H2O+moles unknown) = XH2O from above.
    Substitute moles H2O (from grams/molar mass) and solve for moles unknown.

    You know moles = grams/molar mass. You know grams and moles, solve for molar mass.

    1. 👍 0
    2. 👎 0
    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemestry

    an aqueous solution was prepared by dissolving 1438.0g of a nonelectrolyte in 469.0g of water at 25*c. the Vapor pressure of the resulting solution was found to be 20.5 torr. what is the molar mass of the unknown compound? the

    asked by Nick on March 2, 2011
  2. Chemistry

    At 21.0 °C, a solution of 23.71 g of a nonvolatile, nonpolar compound in 30.64 g of ethylbromide, C2H5Br, had a vapor pressure of 319.7 torr. The vapor pressure of pure ethyl bromide at this temperature is 400.0 torr. Assuming an

    asked by Luke on July 14, 2014
  3. chemistry

    How do intermolecular forces determine the vapor pressure of a liquid? A. A nonpolar compound has a low vapor pressure because of London dispersion forces. B. A compound that can form hydrogen bonds has a low vapor pressure. C. A

    asked by Cortney on March 18, 2015
  4. them

    How do intermolecular forces determine the vapor pressure of a liquid? A. A nonpolar compound has a low vapor pressure because of London dispersion forces. B. A compound that can form hydrogen bonds has a low vapor pressure. C. A

    asked by Jessie on August 19, 2016
  5. chemistry - vapor pressure

    the vapor pressure of pure water at 25C is 23.8 torr. determine the vapor pressure (torr) of water at 25 C above a solution prepared by dissolving 35g of urea (a nonvolatile, non-electrolyte, MW = 60.0G/MOL) IN 76G of water.

    asked by billy on September 13, 2010
  6. Chemistry

    What is the vapor pressure of a solution prepares by dissolving 4.25g of K2O in enough water to preapare 1.25L of Solution at 25 degrees (C)? Assume that the density of the solution is 1.00 g/mL and that the vapor pressure of pure

    asked by Kayla on December 6, 2016
  7. Chem2

    The vapor pressure of water (at 50.0 o C) is lowered by 17.0 torr when 36.1 g of an unknown non-electrolyte is added to 65.56 g water. Determine the molecular weight of the unknown. Density solution = 1.05 g/mL Vapor pressure H2O

    asked by Laura on August 31, 2016
  8. CHEMISTRY

    1. What is the vapor pressure at 25°C of a solution of 1.20g of nephtalene C10H8 in 25.6g of benzone C6H6? The vapor pressure of pure benzene at 23°C is 86.0mmHg the vapor pressure of naphthalene can be neglected. Calculate the

    asked by N COMAS on March 20, 2013
  9. Chemistry

    1) What is the vapor pressure at 25°C of a solution of 1.20g ofnephtalene C10H8 in 25.6g of benzone C6H6? The vapor pressure of pure benzene at 23°C is 86.0mmHg the vapor pressure of naphthalene can be neglected. Calculate the

    asked by N comas on March 19, 2013
  10. 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? I know

    asked by Vic on September 30, 2012

More Similar Questions