which of the following statements describes the correct method of preparation of 1.00 L of 2.0 M urea solution?
Q. This is the answer - Dissolve 120g of urea in enough distilled water to produce 1.00 L of solution. I don't understand how this is the answer. Can someone help me with the math?
Asked by Katie - Tue Feb 2 17:32:54 2010 - - 4 Answers - 0 Comments

A. The chemical equation for Urea (or carbomide) is (NH2)2CO. Calculate the Mol Weight by adding up the individual component MWs: N 14, H 1, C 12, O 12. The total comes to 60. So 120g of Urea is 2 Mols. A 2.0 M (Molar) solution is a solution that contains 2 mols of a compound dissolved in 1 Litre of water. Urea is very soluble in water so 120g would totally dissolve in 1 litre of water. So there is your answer. 120g in 1 L will produce a 2 M solution.
Answered by Bertybign - Tue Feb 2 17:42:12 2010

What is the boiling and freezing point of urea solution?
Q. pls help me...thanks a lot!
Asked by xtian - Sun Dec 2 00:22:46 2007 - - 1 Answers - 1 Comments

A. boiling point is 150 degrees C melting ponit is 135 degrees C
Answered by JT - Sun Dec 2 01:42:28 2007

What is the molarity of urea solution which is isotonic with 50 mM NaCl?
Q. What is the molarity of urea solution which is isotonic with 50 mM NaCl?
Asked by caa - Mon Jan 25 04:44:19 2010 - - 2 Answers - 0 Comments

A. NaCl dissociates to form 2 ions. Urea does not dissociate. Therefore 50mM NaCl = 100mM urea
Answered by Trevor H - Mon Jan 25 06:04:01 2010

A 5% urea solution is hypotonic to a 10% urea solution.?
Q. A 5% urea solution is hypotonic to a 10% urea solution. A. True B. False
Asked by Firm One - Sun Aug 23 17:45:12 2009 - - 1 Answers - 0 Comments

How do I lower the pH to 4.0 of a 4M lithium formate/7.5M urea solution?
Q. How do I lower the pH to 4.0 of a 4M lithium formate/7.5M urea solution?
Asked by Joyce - Sat May 29 21:44:16 2010 - - 1 Answers - 0 Comments

A. add dil HCl
Answered by Colin - Sun May 30 11:04:15 2010

A solution of urea (CH4N20) in water has a vapor pressure of 19.6 torr at 30 degrees celsius. What is the mole?
Q. fraction of urea in this solution I'm stuck on this question please help me :)
Asked by dale s - Fri May 1 22:11:33 2009 - - 1 Answers - 0 Comments

Which of the following statements describes the correct method of preparation of 1.00L of a 2.0M urea solution?
Q. Given that Murea=60.06g/mol a) dissolve 120g of urea in 1.00 kg of distilled water b) dissolve 120g of urea in 880g of distilled water c) dissolve 120g of urea in enough distiled water to produce 1.00L of solution d. Dissolve 120g of urea in 1.00 Litre of distilled water. Can some one please explain to me how i can go about solving this problem? I can never get these dilution problems.
Asked by Spectra - Sat Jun 13 17:07:47 2009 - - 1 Answers - 0 Comments

A. c because M = mol / L(soln)
Answered by Old Science Guy - Sat Jun 13 17:12:19 2009

Suppose blood contains urea,but the external solution is made with no added urea.Will urea leave the?
Q. blood by crossing the diaysis membrane?
Asked by ifmxbeliver - Thu Feb 5 13:12:58 2009 - - 1 Answers - 0 Comments

A. If urea (molecules) are not too large to pass through the membrane (which I think they might be), then it will travel from the area of larger concentration to the area of lower concentration until equilibrium is reached.
Answered by Frankie S - Thu Feb 5 16:49:22 2009

the boiling point of urea in water is 100.13 degree c.calculate the freezing point of the solution(Kf andKb...?
Q. the boiling point of solution of urea in water is 100.13degree c. calculate the freezhing point of the solution(Kf and Kb for water are 1.86k/m and 0.52k/m respectively
Asked by Nimi - Sat Sep 5 13:10:09 2009 - - 1 Answers - 0 Comments

A. boiling point pure water = 100 C delta = 100.13 - 100 = 0.13 0.13 = m x 0.52 m = 0.25 ( molaity of solution) delta T = 0.25 x .186 = 0.47 freezing point = 0 C - 0.47 = - 0.47 C
Answered by Dr.A - Sat Sep 5 13:38:56 2009

What is the boiling point elevation of a solution of 19 g of urea (CO(NH2)2) in 80 g of water?
Q. What is the boiling point elevation of a so- lution of 19 g of urea (CO(NH2)2) in 80 g of water? Kb for water is 0.512 C/m. Answer in units of C.
Asked by Kevin L - Sun Dec 6 00:49:02 2009 - - 2 Answers - 0 Comments

A. find moles, using molar mass: 19 g urea @ 60.06 g/mol = 0.316 moles of urea mass of water = 0.080 kilograms find molality..."m": 0.316 moles of urea / 0.080 kilograms solvent = 3.95 molal find BP elevation: 3.95 molal @ 0.512 C/molal = 2.0 C the boiling point elevation of a solution of 19 g of urea (CO(NH2)2) in 80 g of water is 2.0 C had you asked for the new boiling point, I would have added this boiling point elevation of 2.0C to the normal boiling point given, (i.e. @ 1atm BP of 100.0 C rises to 102.0 C)
Answered by Steve O - Sun Dec 6 08:47:10 2009

What is the freezing point of a solution that contains 23.1 g of urea, CO(NH2)2, in 285 mL water,H2O?
Q. Assume a density of water of 1.00 g/mL .
Asked by shmoopy - Sun Oct 25 03:20:02 2009 - - 1 Answers - 0 Comments

An aqueous solution contains 3% by weight of urea and 7% by weight of glucose,then the moles of water will be?
Q. This question was asked in the entrance test of Bansal Classes in Kota (INDIA) but I am yet to get the answer. Please try to solve it as it is of Xth grade level only.
Asked by THE FUTURE - Wed Mar 25 00:15:20 2009 - - 1 Answers - 0 Comments

A. Are you asking the mole percentage of water of the solution? Find the molecular weights, wu, wg, ww, of the three substances. The number of moles of water of a solution of mass m is .9m/(ww). The total number of particles of a solution of mass m would be m(.03/wu + .07/wg + .9/ww). This means nwater/ntotal = .9/(ww(.03/wu + .07/wg + .9/ww))
Answered by supastremph - Wed Mar 25 00:44:35 2009

How do u remove a membrane from a solution?
Q. If I have a solution in a beaker with urea and albumin, which membrane can I selectively remove the urea from the solution. How would I do this experiment? Which membrane could you choose to selectively remove the urea from the solution? 20, 50, 100, or 200 MWCO
Asked by K - Tue Aug 19 14:34:04 2008 - - 2 Answers - 0 Comments

A. Centrifugation will not separate urea from albumin. You can use a dialysis membrane with the appropriate molecular weight cut-off for the protein. You put the solution of urea and albumin on one side of the membrane, or inside the dialysis bag, and then drop the bag into a beaker of water or buffer. The urea will diffuse out of the bag but the albumin is too large so will stay in the solution inside the bag. If you keep changing the solution in the beaker, eventually you'll have very very little urea inside the bag.
Answered by Simonizer1218 - Tue Aug 19 14:52:33 2008

What is the mole fraction of urea (MW = 60.0 g/mol) in solution prepared by dissolving 16.0 g urea in 39g H2O?
Q. What is the mole fraction of urea (MW = 60.0 g/mol) in a solution prepared by dissolving 16.0 g urea in 39 g water?
Asked by Tyler R - Sun Dec 14 20:36:53 2008 - - 1 Answers - 0 Comments

A. mole urea = 16.0 / 60.0=0.267 mole water = 39 / 18 =2.17 mole fraction = mole species / total number of moles mole fraction urea = 0.267/(0.267 + 2.17)= 0.110
Answered by camarcucci - Sun Dec 14 21:25:57 2008

what is the molar concentration of aqueous urea(NH2)2CO solution which is isotonic with sea water at 25 deg C?
Q. what is the molar concentration of aqueous urea(NH2)2CO solution which is isotonic with sea water at 25 deg C?
Asked by Sheila - Mon Jul 20 08:58:34 2009 - - 1 Answers - 0 Comments

The pH of a 1.00 M solution of urea, a weak organic base, is 7.050.?
Q. Calculate the ka of the protonated urea
Asked by bramos100702 - Thu Jul 1 18:27:14 2010 - - 2 Answers - 0 Comments

A. Urea is a base, so we will denote it as "B". B + H2O <---> BH+ + OH- Kb = [BH+][OH-] / [B] [B] = 1.00 M pH = 7.050; pOH = 6.95; [OH-] = 1.12E-7 M = [BH+] Kb = (1.12E-7)^2 / (1.00) = 1.26E-14 Ka = 1E-14 / Kb = 1.26 Weak bases tend to have strong conjugate acids.
Answered by deadfishfactory - Thu Jul 1 18:39:50 2010

II. An aqueous solution of urea had a freezing point of -0.52 find the osmotic pressure of the same solution
Q. this is a chemistry question
Asked by Kalvin - Mon Apr 30 02:30:00 2007 - - 1 Answers - 0 Comments

A. This problem deals wiht 'colligative properties' - which include freezing point drepression and osmotic pressure. The freezing point depression may be calculated as (delta)T = K*m*i where K is the cryoscopic constant of water (1.868 K kg mol-1), m the molality of the solute (urea) and i a number that tells you into how many particles the solute dissociates ( i=1 for urea). With this you can calculate the molality of the urea solution and afterwards the osmotic pressure (pi): (pi) = i*M*R*T where M is the molarity of the solution, R the gas constant (0.08314 l bar mol-1 K-1), T the temperature (I'd use 25 C) and i the same as above. I assume that you may neglect the difference between molarity and molality and use m=M. Otherwise you… [cont.]
Answered by Kenneth R - Mon Apr 30 03:23:18 2007

what is the mole fraction of urea(CON2H4) in an aqueoues solution that is 10.0% urea by mass?
Q. what is the mole fraction of urea(CON2H4) in an aqueoues solution that is 10.0% urea by mass?
Asked by Abib A - Sun Apr 13 20:14:52 2008 - - 1 Answers - 0 Comments

A. The molar mass of Urea is 60.07 g/mol. The molar mass of Water is 18.02 g/mol. A 10.0% (by mass) solution contains 1.0 grams of Urea for every 10 grams of solution. This means that there are 9.0 grams of water. 1.0 g / 60.07 g/mol = 0.01665 moles of Urea. 9.0 g / 18.02 g/mol = 0.4994 moles of Water. The mole fraction of Urea = Moles Urea / Total moles 0.01665 moles / (0.01665 moles + 0.4994 moles) = 0.01665 moles / 0.5161 moles = 0.03226
Answered by Richard - Tue Apr 15 01:20:07 2008

Calculate the boiling point of a solution of 30.0g of Urea in 250g of water?
Q. Urea, NH2CONH2 is a nonvlatile nonelectrolyte. Calculate the boiling point of a solution of 30.0g of Urea in 250g of water. (Kf = .512*C/m) Atomic weights C: 12.01 H: 1.008 O: 16.00 N: 14.00 The answer is 101.0, but I need help figuring out how to solve the problem to review for my final. Thank you!
Asked by brambo20hooah - Sat Mar 13 19:14:11 2010 - - 1 Answers - 0 Comments

A. moles urea = 30.0 / 60 g/mol=0.5 m = 0.5 / 0.250=2 delta T = 0.512 x 2 = 1.0 boiling point = 100 + 1.0 = 101.0 C
Answered by Dr.A - Sun Mar 14 10:49:48 2010

Calculate the osmotic pressure of a 0.217M solution of urea (NH2)2CO at 22C.?
Q. Calculate the osmotic pressure of a 0.217M solution of urea (NH2)2CO at 22C.?
Asked by ltaylor4life - Mon Nov 17 18:27:15 2008 - - 1 Answers - 0 Comments

A. T = 22 + 273 = 295 K osmotic pressure = 0.217 x 0.0821 x 295 = 5.26 atm
Answered by Dr.A - Tue Nov 18 15:37:57 2008