Chemistry

posted by .

Unknown Acid: #2
Mass of Unknown solid acid transferred:0.414g
Volume of volumetric flask: 100.00 mL
Concentration of NaOH: 0.0989 M
Aliqot of acid titrated with NaOH: 25.00 mL
Average volume of Naoh from titration: 13.9 mL

Here's where I need help:

No of moles NaOH used: ? mol
--This is wat i did:
. n=C.V
. =(0.0989M)(0.001375L)
. =0.001375mol



Molar ratio of base to acid?
. Diprotic acid. so 2:1

The unknown acid is mono, di, triprotic acid:? Diprotic

The titration reaction was:?
. H2A + 2NaOH --> 2H2O +Na2H
. where A is the unknown acid compound

No. of moles acid in 25 mL solution:?

. HELP >.<' I don't understand the
. question :P But here is wat i think
. of it. (0.414g)x(25mL/100ml)
. =0.1035 g of acid used in
. the titration.
. HELP?!??

Gram-Molecular acid in 25mL solution?

HELPPPP ! ! ! ! :( :(

ANY AMOUNT OF HELP WILL BE GRATEFUL! PLZ N THANK YOU :D


No one has answered this question yet.

  • Chemistry -

    Yes, moles NaOH = M x L; however, you didn't convert 13.9 mL correctly. It should be 0.0139 L.

    0.414 x (25 mL/100 mL) is correct.

    So if the acid is diprotic (I assume you were told that), then moles H2A = 1/2 moles NaOH = ??
    Now molar mass acid is
    n = g/molar mass and
    molar mass = grams H2A/moles H2A.

  • Chemistry -

    Thats exactly what i was thinking of doing. However a friend of mine dvided the molar mass of the acid by 4 in the end. Andinsists that its the riht thing to do. I don't understand why he did that but it seems toi have gotten him the right answer :S

  • Chemistry -

    Certainly that will work. The grams of acid/mole = molar mass.
    So if you use 4 times the acid, then divide the final result by 4 you get the same answer as dividing by 4 first before dividing by moles. I wonder if this is what you did on the other problem I just did. You had 1.2/moles and your answer was 4x too high which is why you had that huge molar mass of 1304 something.

  • Chemistry -

    Thanks Alot DrBob222 :D rele means alot ! ! :D

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Chemistry, Buffers, pH

    Hi could someone please help me in the next 5 minutes with this question: Given this data: mass of unknown acid 1.4671g Volume of NaOH used in titration 18.47mL Concentration of the NaOH used 0.2403M pH of the original acid solution …
  2. Chemistry

    I there, this is my lab worksheet, I am having trouble filling it out. Please help me with it. Expt #1- Molecular Weight of Unknown Acid Unknown Acid: #3 Mass of Unknown solid acid transferred:1.0g Volume of volumetric flask: 100.00 …
  3. Chemistry

    Expt #1- Molecular Weight of Unknown Acid Unknown Acid: #2 Mass of Unknown solid acid transferred:0.414g Volume of volumetric flask: 100.00 mL Concentration of NaOH: 0.0989 M Aliqot of acid titrated with NaOH: 25.00 mL Average volume …
  4. Chemistry

    Find the Molecular weight of unknown acid #5... Mass of acid #5 = 1.200g Volume (acid was mixed in) = 100ml (distilled water) Conectration of NaOH = 0.989 M Aliquot of acid titrated with NaOH = 25ml = 0.025 L Average volume of NaOH …
  5. Chemistry, pH, Buffers

    Please help!! Given this data: mass of unknown acid 1.4671g Volume of NaOH used in titration 18.47mL Concentration of the NaOH used 0.2403M pH of the original acid solution 2.16 pH of the final acid solution 3.49 Show me how do I calculate …
  6. College Chemistry

    You weigh a sample of a monoprotic unknown acid and dissolve it in 50.00 mL of distilled water. Exactly half of this solution is titrated with Sodium Hydroxide to the phenolphthalein end point. The pH of the other half of the original …
  7. Chemistry

    An unknown solid acid is either citric acid or tartaric acid. To determine which acid you have, you titrate a sample of the solid with NaOH. The appropriate reactions are as follows: Citric acid: H3C6H5O7 (aq) + 3NaOH (aq) -> 3H2O …
  8. chemistry

    You weigh a sample of a monoprotic unknown acid and dissolve it in 50.00 mL of distilled water. Exactly half of this solution is titrated with Sodium Hydroxide to the phenolphthalein end point. The pH of the other half of the original …
  9. Chemistry

    For my lab, I have been asked to calculate the pKa of an unknown amino acid. We titrated the unknown amino acid with NaOH. The pKa needs to be calculated using the Henderson Hasselbach Equation. Obviously you can just get the pH from …
  10. Chemistry

    We will calculate the amount of acid to use in each titration. Assume that you are using 0.0512 M NaOH(aq). A good volume of NaOH(aq) to use per titration is 15 mL. From this molarity and volume, the moles of NaOH can be calculated. …

More Similar Questions