1. Questions

mathematics

What is the vapor pressure at 23°C of a solution of 1.20 g of naphthalene, C10H8, in 25.6 g of benzene,
C6H6? The vapor pressure of pure benzene at 23°C is 86.0 mmHg; the vapor pressure of naphthalene
can be neglected. Calculate the vapor-pressure lowering of the solution.

  1. 👍
  2. 👎
  3. 👁
  4. ℹ️
  5. 🚩
anis

  1. The Raoult's law says that the vapor pressure of a solvent in a solution is always lower than the vapor pressure of the pure solvent. The vapor pressure lowering is directly proportional to the mole fraction of the solute. In mathematical terms that means:

    ΔP = (1)

    ΔP is the vapor-pressure lowering of the solution is the molar fraction of the solute and is the vapor pressure of the pure solvent (86,0 mmHg)

    The moles of naphthalene are:
    9,36x10⁻³ moles solute

    The moles of benzene are:
    0,328 moles solvent

    Molar fraction of solute is:
    0,0278

    Replacing in (1)
    ΔP = 2,39 mm Hg

    Therefore, the vapor-pressure lowering of the solution is 2,39 mmHg

    1. 👍
    2. 👎
    3. ℹ️
    4. 🚩
    Lucy

Respond to this Question

First Name

Your Response

Similar Questions

  1. 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? I got an answer of 15.45 torr and it marked me incorrect and said "Your

  2. chemistry

    Calculate the enthalpy of fusion of naphthalene (C10H8) given that its melting point is 128 Celsius and its entropy of fusion is 47.7 J (k*mol) .

  3. chemistry

    A 1.60 g sample of a mixture of naphthalene, C10H8, and anthracene, C14H10, is dissolved in 20.0 g benzene, C6H6. The freezing point of the solution is 2.81oC. What is the composition as mass percent of the sample mixture?

  4. Mole fraction of a vapor pressure?

    If 0.380 mol of a nonvolatile nonelectrolyte are dissolved in 3.00 mol of water, what is the vapor pressure P(H2O) of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 C. I got this answer correct: 21.1

  1. Chemistry

    If a mothball (C10H8) has a mass of 1.32 grams, how many naphthalene molecules does it contain? If I'm right just multiply 1.32g by 6.022*10^23 and the answer is 7.949*10^23 molecules. Is this right?

  2. Chemistry

    What will be the freezing point of a solution made by dissolving 5.25 g of naphthalene (C10H8) in 100.0 g benzene (C6H6?). The normal freezing point of benzene is 5.5°C and K f (benzene) is 5.12°C / m.

  3. Chemisty-Freezing Points

    The freezing point of benzene is 5.5°C. What is the freezing point of a solution of 8.50 g of naphthalene (C10H8) in 425 g of benzene (Kf of benzene = 4.90°C/m)? delta T = Kf m m = mols/kg solvent. Change 8.5 g naphthalene to

  4. chemistry

    the vapor pressure of water at 45.0 °c is 71.93 mmhg. Calculate the vapor pressure of a solution of 1.50 m Al(NO3)3 at this temperature (assume 100% dissociation)

  1. Chemistry

    The vapor pressure of pure acetone (propanone) is 266 torr. When a non-volatile solute is added, the vapor pressure of acetone above the solution falls to 232 torr. What is the mole fraction of acetone in the solution? Show work.

  2. Chemistry

    Benzene (C6H6) has a normal freezing point of 5.50oC and a density of 0.88 g/mL. When 1.28 g of naphthalene (C10H8) is dissolved in 125 mL of benzene, the freezing point of the solution is 5.03oC. Determine the molal freezing

  3. chemistry -check over work

    Naphthalene (C10H8)is a solid aromatic compound often sold as mothballs.The complete combustion of this substance to yield CO2(g)and H2O(l)at 25 ْC yields -5154 kJ/mol. A. write balanced equation for the combustion of C10H8.

  4. Chemistry

    How many grams of sulfur (S8) must be dissolved in 100.0 naphthalene (C10H8) to make a 0.13 solution? answer in grams.

View more similar questions or ask a new question.