[CHOOHO]

Two experiments are carried out to determine the molecular formula of a monoprotic organic acid containing only carbon, hydrogen and oxygen. First, combustion of 3.332 grams of acid produces 8.642 grams of carbon dioxide and 1.764 grams of water. In a second experiment, titration of 0.4326 grams of acid requires 18.15 mL of 0.1752 M NaOH solution to reach a suitable endpoint.

I need to find the moles of O2 gas needed for the combustion reaction and the simplest formula for the acid. I know what a monoprotic acid is but there are various kinds. I have tried at this for a while now but am so stuck. Could someone be of assistance?

[Arkcon]

Well, lets start with something simple that will help you start to figure this problem out.  Can you write unbalanced chemical reactions for the two reactions you've been given?  You can't completely balance them, because you don't know the formula of the acid.  But you can start converting the grams of products and O2 and NaOH into moles, as a start.

[CHOOHO]

I could only come up with one of the unbalanced chemical reactions;
?(aq) + O2(g) ---> CO2(g) + H2O(l)
I did however find that there are .0031 moles of NaOH, 0.1964 moles of CO2, and 0.0979 moles of H2O.
Trouble arised when trying to write even a rough formula for the titration problem.

I am very very stuck. Help from there?