Vapor pressure Definition and 109 Threads

  1. S

    Organic Compound's Mass from Vapor Pressure

    Is this even correct? A natural product (MW = 150 g/mol) distills with steam at a boiling temperature of 99 C at atmospheric pressure. The vapor pressure of water at 99 C is 733 mmHg. a. Calculate the weight of the natural product that codistills with each gram of water at 99 C...
  2. J

    Vapor pressure of Water calculation

    Ok, I need to calculate the vapor pressure of water. All the information I am given is that the temp is 43.0 C, and I know the total pressure of the system is 758.3 torr. Is there anyway I can calculate this using the Pwater = Ptotal - Pair equation? There is also another equation that...
  3. S

    What Happens to Ice at 0°C in a Vacuum Due to Vapor Pressure?

    Can anyone help to explain what vapor pressure does...i know what it is...but how can it be used if you put a cube of ice at 0 degrees C, in a vacumed container (amospheric pressue equals zero) won't the ice all go to gas, since its vapor pressure is greater than the atmospheric pressure...
  4. A

    What is the Van't Hoff factor for NaCl in seawater?

    X_1=\frac{n_1}{n_1+n_2}\implies n_2=\frac{n_1-X_1n_1}{X_1} where n1 is the moles of solvent and n2 is the moles of solute. 22.98=X_1\left(23.76\right)\implies X_1=.9672 and 1000 g of water is equal to 55.49 mol (n1), so plugging this all in gives: n_2=1.88\text{mol} which would be...
  5. A

    Calculating Vapor Pressure Lowering for Glucose-Water Solution at 25oC

    I calculated that there is 41/90 mol glucose and 92/3 mol water. Then I calculated the molar fraction of solvent in the solution, which I found to be .985. Next I multiplied the .985 by 23.76 mmHg and came up with 23.4 mmHg. To find the "lowering," I subtracted this from 23.76 coming up with...
  6. P

    Oentane is a liquid with a vapor pressure of 512 Torr at 25C

    Oentane is a liquid with a vapor pressure of 512 Torr at 25C; at the same temperature, the vapor pressure of hexane is only 151 Torr. what composition must the liquid phase have if the gas hase composition is to have equal amounts of pentane and hexane? Do I use p = i M R T to solve for the...
  7. C

    Calculating Vapour Pressure for 1L Container with 5mL Water at 20°C

    a 1 L container with 5 mL of water held at 20degcel I have to figure out the vapour pressure. I was told to use PV=nRT..but how do I find n? thanks
  8. P

    Vapor Pressure in fresh vs salt water

    For water at 30°C, when 100 g of pure water the vapor pressure is 31.82 mm Hg and when 50g of NaCl dissolved in 100g of water vapor pressure is 27.68 mm Hg The vapor pressure of pure water is different than the vapor pressure of water in a salt water solution. Explain why. Can anyone...
  9. F

    How to Calculate the Mole Fraction in a Pentane-Hexane Solution?

    Hi I have difficulties with a problem that my teacher gave in assignement. Teh teacher said it was a bit higher than our level but I think it far above what I am able to do! so here it is : The vapor pressure in equilibrium with pentane-hexane solution at 25°C has a mole fraction of...
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