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.

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.

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

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.

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

To find the number of moles of acid in 25 mL solution, you need to convert the mass of the acid used in the titration to moles.

First, let's calculate the mass of acid used in the titration. You have already stated that you used 0.414 g of the unknown solid acid in the experiment.

Next, we need to find the molar mass of the acid. The molar mass can be determined using the periodic table. If you have the chemical formula of the acid, you can add up the atomic masses of each element in the formula to get the molar mass.

Once you have the molar mass, you can use the formula:

moles = mass / molar mass

Substituting the values into the formula, you get:

moles of acid = 0.414 g / molar mass of acid

The result will be the number of moles of acid used in the titration.

To find the gram-molecular mass of the acid in the 25 mL solution, you would multiply the molar mass of the acid by the number of moles of acid in the solution.

gram-molecular mass = moles of acid * molar mass of acid

You can then use this information to answer any further questions related to the unknown acid.