Chemistry

posted by Joy

A solution is made by mixing 42.0 mL of ethanol, C2H6O, and 58.0 mL of water. Assuming ideal behavior, what is the vapor pressure of the solution at 20 C in torr?
Values at 20C
ethanol density: 0.789 g/mL & vapor pressure (torr): 43.9 torr
water: denisty: 0.998 g/mL & 17.5 torr

Any steps would be GREATLY appreciated!

  1. DrBob222

    Calculate moles H2O.
    Calculate moles EtOH.
    Calculate XH2O
    Calculate XEtOH.
    Calculate pH2O
    Calculate pEtOH.
    Total P = pH2O + pEtOH

  2. Joy

    Hi Dr Bob, is this right so far?
    mass h2o = (d)(v) = (0.998 g/mL)(58 mL) = 57.884 g
    57.884 g H2O/18g H2O = 3.2157 mol H2O
    mass ethanol = (0.789 g/mL)(42 mL) = 33.138 g
    33.138 g C2H6O/46.0687 g C2H6O = 0.719 mol C2H6O

    molality (m) = 0.71937 mol C2H6O/0.057884 kg H2O = 12.43 m

    xH2O = 12.45/(12.43+3.2157) = 0.794
    xEthanol = 12.43/(12.43 + 0.719) = 0.91
    ?

  3. DrBob222

    Hi Dr Bob, is this right so far?
    mass h2o = (d)(v) = (0.998 g/mL)(58 mL) = 57.884 g
    57.884 g H2O/18g H2O = 3.2157 mol H2O
    mass ethanol = (0.789 g/mL)(42 mL) = 33.138 g
    33.138 g C2H6O/46.0687 g C2H6O = 0.719 mol C2H6O

    You are ok to here with moles.
    You don't need molality. You want mole fraction. mole fraction EtOH = XEtOH = moles EtOH/total moles. mole fraction H2O = XH2O = moles H2O/total moles
    Then pH2O = XH2O*PoH2O and
    pEtOH = XEtOH*PoEtOH.
    Total P = pH2O + pEtOH.



    molality (m) = 0.71937 mol C2H6O/0.057884 kg H2O = 12.43 m

    xH2O = 12.45/(12.43+3.2157) = 0.794
    xEthanol = 12.43/(12.43 + 0.719) = 0.91
    ?

  4. Joy

    i got it! thanks Dr Bob

Respond to this Question

First Name

Your Answer

Similar Questions

  1. CHEMISTRY

    At 63.5 degreesC, the vapour pressure of H2O is 23.3kPa and that of ethanol is 53.3kPa. A solution is made by mixing egual masses of H2O and C2H5OH. a. what is the mole fraction of ethanol in the solution?
  2. chem

    A 4.1 L sealed bottle containing 0.25 g of liquid ethanol, C2H6O, is placed in a refrigerator and reaches equilibrium with its vapor at -11°C. The vapor pressure of ethanol is 10 torr at -2.3°C and 40 torr at 19°C. (a) What mass …
  3. chemistry

    the vapor pressure of ethanol at 20c is 44 mmHg and the vapor pressure of methanol at the same temperature is 94mmHg. A mixture of 30.0 g of methanol and 45.0 g of ethanol is prepared (and can be assumed to behave as an ideal solution). …
  4. Chemistry

    A solution is made by mixing 30.0 mL of ethanol, C2H6O, and 70.0 mL of water. Assuming ideal behavior, what is the vapor pressure of the solution at 20 °C?
  5. Chem 2

    A solution is made by mixing 47.0 mL of ethanol, C2H6O, and 53.0 mL of water. Assuming ideal behavior, what is the vapor pressure of the solution at 20 °C?
  6. Chemistry II

    A solution is made by mixing 38.0 mL of ethanol, C2H6O, and 62.0 mL of water. Assuming ideal behavior, what is the vapor pressure of the solution at 20 °C?
  7. Chemistry

    A solution is made by mixing 37.0 mL of ethanol, C2H6O, and 63.0 mL of water.?
  8. chemistry

    What is the percent by volume (% v/v) of a solution made by mixing 12 ml of ethanol (C2H5OH) with 48 ml of water?
  9. chemistry

    a solution is made by mixing 38.0 ml of ethanol C2H6O, 62.0mL of water. assuming ideal behavior, what is the vapor pressure of the solution at 20 C
  10. Chemistry

    Assuming the solution you used was 95% ethanol by volume and that the density of ethanol is 0.816g/mL, how much water and carbon dioxide are produced in the experiment?

More Similar Questions