[dob33]

I can't seem to figure out how to approach this problem:

An unknown acid is found to have 2 hydrogen atoms, meaning it's h2(and unknown elements).

A biologist neutralized a sample of 0.1235-g of this acid with 15.55 ml of a 0.1087 M NAoH.  A chemist combusted a 0.3469-g sample of this acid and found the sample produced 0.6268 grams of CO2 and .2138 grams of H2O.

WHat is the molar mass of the acid?

So far I've figured out the moles and the % of the weight of the unknown acid, but I'm not sure if I'm on the right track.  Would would be the appropriate steps to solve this?

[Dan]

So far I've figured out the moles and the % of the weight of the unknown acid, but I'm not sure if I'm on the right track.

Please show your work - without it we can't be sure you're on the right track either...

[dob33]

Balanced Chemical Equation:

H2A + 2 NAOH --> Na2(A/unknown) + 2 H20

Combustion equation:

H2A + O2 --> CO2 + H20

Mols of "A"

.1087 g NaOH X (1 mol NaOH/39.998 g NAOH) X (1 mol H2A / 2 Mol NaOH) = .00135881 mol H2A



I'm  not really sure where to go from here.  I'm just looking for the steps to figure it out.  I can't find it in my notes, and I've looked at it for hours. 

[dob33]

It seems to me it's made of H2C and O, but I'm not sure how to calculate the weight of those seeing as I don't know the number of them.  If I subtract the O2 from both sides I'm left with H2 and CO, but how many O's?

[Borek]

Combustion analysis gives you an empirical formula, have you found it?