Chem=continued

I'm currently working on a lab in which I have to make the solution boil at 245 degrees F. The solution will be a mix of ethylene glycol and I have to caluculate the volumes of water and solute needed to make the solution.

here's my work so far.
X= mL C2H4(OH)2
175mL-X=mL H20

water boils @ 100 degrees C
my bp is 118.33 degrees C

given:
kb= .515 degrees C kg/mol
d of C2H4(OH)2 = 1.1088 g/mL

delta Tb = (kb*g*i)/GMW*kg

18.33 degrees c = (.515)*(1.1088)*(1)/(62.08g/mol)*(175-X(.9970)/1000)
18.33 = .571032X/(62.08)(175-X)(.9970)/1000
18.33 = 571.032 X/(62.08)(174.475-.9970X)
18.33 = 571.032X/ (1031.408-61.89376X)

now i'm stuck. i don't understand how to get x by itself from here. is what i've done so far correct?
thank you.

I got cross eyed looking at all the numbers. Let me break it down. Also, you don't say how much you want to make. I have assumed 100 g water as the solvent.
Delta T = Kb*m (i is 1).
118.33-100 = 0.515*m
solve for molality.

molality = mols solute/kg solvent = mols solute /0.1
solve for moles solute.

mols solute = grams solute/molar mass solute

If you want to use volume for the ethylene glycol instead of weighing it, then volume = mass desired/density

I hope this helps.

  1. 👍
  2. 👎
  3. 👁
  1. thank you. i'm confused thought....i tried to use a formula that already had molality in it because i don't have a mass to use, hence the g/GMW kg portion. i need to use 175 mL and make it boil at 245 degrees F.

    1. 👍
    2. 👎
  2. Can you make up any quantity, then use 175 mL of that solution or must you make up exactly 175 mL. If the former, the procedure I outlined in my previous post will work ok but you will end up using more chemicals than is necessary AND you will have much more solution that is unused. If the latter, I don't know how to do it except by trial and error.
    Using 118.33-100 = 0.515 m we can determione m = 35.59 molal.
    Then, for 100 mL H2O = 0.100 kg,
    m x kg solvent x molar mass solute = g solute
    35.59 x 0.100 x 62.07 = 221 g ethylene glycol which is far more than you need since that would be of the order of 300 mL solution. Next, try, 50 mL H2O.

    35.59 x 0.050 x 62.07 = 110.5 g ethylene glycol or 99.6 mL. ASSUMING the volumes are additive, and I'm not sure they are, then 99.6 + 50 mL = 150 mL.

    Next try. 58.5 mL H2O
    35.59 x 0.0585 x 62.07 = 129.2 g ethylene glycol or 116.6 mL, then 116.6 + 58.5 = 175, again assuming they are additive. SO, 58.5 mL water (which you assume to be 0.0585 kg water) + 116.6 mL ethylene glycol will give you 175 mL of a solution that should boil at 118.33 IF the water and ethylene glycol are additive in volume.

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    A chemist wants to make 150 mL of a 1.26 M solution of carbonic acid to be used in the lab. How many grams of H2CO3 does the chemist need to make this solution? I converted mL to .150L, multiplied .150*1.26= =0.189 to get mol.

  2. Chemistry

    Visit: VIRTUAL LAB: Textbook Style Limiting Reagents Problems on Chem collective Windows and Macintosh users: Please use Firefox or Chrome web browser. The simulation will run on most laptops, desktops and touch-enabled devices

  3. Math (Algebra)

    A chemistry student needs to make 60 liters of a 30% alcohol solution. He has a 20% alcohol solution and a 40% alcohol solution in the lab. How many liters of each strength does he need to mix together *The system of equations I

  4. chemistry

    1) If 358 g of KNO3 are dissolved in 650 mL of water at 80°C, at what temperature will solid settle out when it is cooled? 2) Give 2 ways, quantitatively, that a solution of 80 g of NaNO3 in 100 mL of water at 70°C can be made

  1. Science

    When entering science lab, which of the following should be done by science students? Students should start working on their experiment. Students must talk to their lab partner to see what they need to do next. Students must wait

  2. Chemistry

    An aqueous solution of NaCl freezes at -1.6ºC. At what temperature will it boil? Given that K(b) for water is 0.52 deg m^-1.

  3. Chem

    You made 100.0 mL of a lead(II) nitrate solution for lab but forgot to cap it. The next lab session you noticed that there was only 80.7 mL left (the rest had evaporated). In addition, you forgot the initial concentration of the

  4. Chemistry

    Visit: VIRTUAL LAB: Textbook Style Limiting Reagents Problems on Chem collective Windows and Macintosh users: Please use Firefox or Chrome web browser. The simulation will run on most laptops, desktops and touch-enabled devices

  1. Chemistry

    I found the following procedure to prepare starch indicator solution on a website:- To prepare starch indicator solution, add 1 gram of starch (either corn or potato) into 10 mL of distilled water, shake well, and pour into 100 mL

  2. chem

    Quantitative analysis of soda ash by double indicator *why there is a need to boil distilled water in the preparation of base solutions? *why a mixture of NaOH and NaHCO3 is incompatible? *why there is a need t o boil the solution

  3. Algebra 1

    A lab technician has a 15 percent alcohol solution and a 35 percent alcohol solution. She wants to make 100 gallons of a 29 percent alcohol solution. How much of the 15 percent solution should she use?

  4. Analytical CHM

    Calculate the theoretical amounts of 0.1000 M NaOH titrant used to titrate 0.8 and 0.9 g KHP Please show step by step solution , i need the correct significant figures and units to finish up the rest of the lab correctly i found

You can view more similar questions or ask a new question.