Chemistry

A student has 100.0 mL of an unknown solution of Vitamin C. She removes 1.00 mL of this solution, dilutes it to 50.0 mL, and titrates this second solution with an iodine solution solution that 8.5x1^-4 M. 6.60 mL of iodine solution is required to reach the endpoint.
1. How many moles of iodine were added to the vitamin C solution to reach the endpoint of this titration?
2. If at the end point, the moles of vitamin C and the moles of iodine are equal, how many milligrams of vitamin C were in the original 100.0 mL?
3. What is the molarity of the original unknown vitamin C solution (prior to dilution)?

  1. 👍 0
  2. 👎 0
  3. 👁 83
  1. You would do well to proof your posts because this one is garble.
    A. Doesn't the problem say 6.60 mL is required? It's hard to tell from the post.
    B. moles vit C = M I2 x L I2 = ?
    g vit C titrated = mols vit C x molar mass vit C.
    g vit C in original soln = g tirated x 100/1 = ?
    C. M original soln = moles/L soln = moles in original soln/0.1L = ?

    1. 👍 0
    2. 👎 0
  2. we are not given the molar mass of the vit. C. how are we supposed to find the milligrams of vit C are in the orginal sample?

    1. 👍 0
    2. 👎 0
  3. Calculate it. Here is a link.
    176.12
    http://www.google.com/search?q=vitamin+c&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

    1. 👍 0
    2. 👎 0
  4. to find the total moles of iodine, do you just multiple 8.5x10^-4 by .00660 L?

    1. 👍 0
    2. 👎 0
  5. If that's the M and L, yes. You made a typo there and I can't tell what you used.

    1. 👍 0
    2. 👎 0
  6. to find the molarity of the original vit C do you just divide the moles found in 1 divided by 0.001 L or 1.0 mL?

    1. 👍 0
    2. 👎 0
  7. Nevermind. i figure it out. Thank you so much for your help!

    1. 👍 0
    2. 👎 0
  8. Read my instructions; part C.
    C. M original soln = moles/L soln = moles in original soln/0.1L = ?
    It's mols/L and you had 100 mL (0.1L) of the original solution.

    1. 👍 0
    2. 👎 0
  9. would 5.61x10^-5 make sense for the molarity for the original unknown sample of vit C solution prior to dilution?

    1. 👍 0
    2. 👎 0
  10. If I didn't make an error, you and I differ by a factor of 100. Did you correct the titrated amount to the original solution by multiplying by 100?
    1. mols I2 = M x L = 0.00660 x 8.5E-4 [= 5.61E-6 mols vit C in titrated sample.
    2. 5.61E-6 x (100/1) = 5.61E-4 moles in the original solution ( you took a 1 mL aliquot from the 100 mL original).
    3. M = moles/L = 5.61E-4/0.1L = 5.61E-3M

    1. 👍 0
    2. 👎 0
  11. in step 2 aren't you supposed to divide by the molar mass of vitamin C (176.12)?

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    A student has 100.0 mL of an unknown solution of Vitamin C. She removes 1.00 mL of this solution, dilutes it to 50.0 mL, and titrates this second solution with an iodine solution solution that 8.5x1^-4 M. 6.60 mL of iodine

    asked by Cassandra on March 12, 2012
  2. Chemistry

    A student has 100.0 mL of an unknown solution of Vitamin C. She removes 1.00 mL of this solution, dilutes it to 50.0 mL, and titrates this second solution with an iodine solution that is 8.5 × 10-4 M. 6.60 mL of iodine solution

    asked by Shelley on March 12, 2012
  3. Science

    A vitamin C tablet was dissolved in 50.0 mL of water. The resulting solution was titrated to the equivalence point with 28.5 mL of 0.100 M I3− solution. What is the starting mass of the tablet assuming the tablet is 100% vitamin

    asked by Clay on September 21, 2015
  4. Chemistry

    A sample of fresh grapefruit juice was filtered and titrated with the above I2 solution. A 100 mL sample of the juice took 9.85 mL of the iodine solution to reach the starch endpoint. a. What is the concentration of vitamin C in

    asked by Anonymous on April 13, 2010
  5. chemistry

    . A sample of fresh grapefruit juice was filtered and titrated with the above I2 solution. A 100 mL sample of the juice took 9.85 mL of the iodine solution to reach the starch endpoint. a) What is the concentration of vitamin C in

    asked by traci-ann on October 10, 2017
  6. Chemistry

    I have this question which I believe I solved correctly, but I was wondering if someone could look it over to make sure? The question is... Assay for Vitamin A (a fat soluble vitamin) required an extraction step into ether. In

    asked by Rob on January 11, 2013
  7. Chemistry

    A student followed the procedure given in the lab exercise to determine the ascorbic acid content in a commercial vitamin C tablet. The students prepared the solution using a 0.460 g vitamin C tablet. The titration required 40.00

    asked by R on November 22, 2016
  8. Chem 2

    Vitamin K is involved in normal blood clotting. When 1.56 g of vitamin K is dissolved in 25.0 g of camphor, the freezing point of the solution is lowered by 5.23 °C. . Calculate the molar mass of vitamin K.

    asked by Bri on February 20, 2014
  9. Analytical chemistry

    Calculate the expected concentrations of vitamin B6 and caffeine in the stock solution assuming exactly 0.0506 g of pyridoxine hydrochloride (vitamin B6) and 0.1253 g of caffeine are dissolved in a 100 mL volumetric flask.

    asked by Angel on November 23, 2016
  10. Chemistry

    Mass of unknown solution=25.671 Mass ethanol =8.243 Assuming that prior experiments have shown the single-step extraction removes only 72.0 % of the ethanol, the mass of ethanol in your original unknown is 11.45 Mass percent

    asked by Forrest on January 29, 2012

More Similar Questions