chemistry

posted by mohit

500g urea aq. Sol. Has mole fraction 0.2 what is molality of sol.

  1. lol

    answer to how much heat is required to raise the temperature of 68.0 g of AIF3 from 25 degrees celsius to 80.0 degrees celsius

  2. DrBob222

    Your question is answered above.

  3. DrBob222

    The mass of the solution is 500. How much is urea and how much is water?
    Let X = g urea
    and 500-x = grams H2O
    Then mols urea = X/60
    mol H2O = (500-X/18)

    Then
    nurea/(nurea + nH2O) = 0.2
    (X/60)/{[(X/60)] + [(500-X)/18]} = 0.2

    I solved for X and obtained about 227 g for urea and 273 g H2O. You can work that out but that's very close to a mole fraction for urea of 0.2.
    Then n urea = about 3.8
    n H2O = about 15.2

    From above we had 227 g urea (about 3.8 mols) and 273 g H2O
    molality = (mols solute)/(kg solvent)
    mols solute = about 3.8
    kg solvent = about 0.273
    m = ?
    My numbers are estimates; you should recalculate each step.

Respond to this Question

First Name

Your Answer

Similar Questions

  1. pharma medicine

    you are combining 50ml of a 20%sol,150ml of a 15% sol.,and 200ml of a 35% sol.what is the final % concentration of the mixed sol. how many total grams are is the final sol?
  2. chemistry

    An x molal sol. of a compoumd in benzene has mole fraction of solute equal to 0.2 the value of x will be?
  3. Chemistry

    You mix 19.5 gallons of a mixture containing 12 wt% NaCl (sol'n density = 1.0837 g/cm^3) with V2-gallon sol'n that is 20 wt% NaCl (sol'n density = 1.1453 g/cm^3). Needed mixture is 19 wt% NaCl Whats the V2 in gallons?
  4. Chemistry

    Calculate the molality of of a sol'n whose density is 1.15 g/ml
  5. chemistry

    Mole fraction of NaOH is aquous sol 0.15 Find molarity of the solution, %w/w, if the density of solution is 1.25 g/ml
  6. chemistry

    A sol n contains 37g cuso4 and 111g water . Calculate the concentration by mass /c of sol n.
  7. Chemistry

    Molality of aqueous solution of urea is 4.What will be the mole fraction ofH2O?
  8. s

    he a 1.00 m sol'n of nitric acid. how many ml of this sol'n will he need to add to the soil to completely react with 56.8 g of al(oh)3
  9. Chemistry

    1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right?
  10. CHEMISTRY

    1. Not sure of how to do the calculations... Make a 0.200 m solution of NaCl in a 100. mL volumetric flask. ... Solution A's question or statement is the same but with M (molarity) Is this right?

More Similar Questions