[Malekyth89]

1. The problem statement, all variables and given/known data
 1)After analyzing an organic substance ,it came to this: 29,752% Carbon;5,785%Hydrogen:26,446% Sulpur and 11,57% Sodium.It is also that known that between the Oxygen mass and Sodium mass ,in a mole of substance analyzed,it's a difference of 18 grams.Determinate the molecular formula of the substance.

 2) Volume of 0,56 dm3 of a gas hydrocarbon weights in normal conditions 1,45 grams.Knowing that the atomic ratio of the elements of the hydrocarbons is C : H = 2 : 5 fiend the molecular formula of the hydrocarbons.
 A)CH4 B)C2H6 C)C4H10

 3) A probe from a organic substance whit the raw(brute) formula CnH2nO who contains 0,6 moles makes in oxidation 79,2 mini grams CO2.Determinate the molecular formula of the organic substance

 How i do these problems?


 2. Relevant equations

 It's the first semester and it's using basic formulas plus it will use the empirical formula to fiend the formula at the end i think

 3. The attempt at a solution
 I dont know how to do it :/ i mean i may know how to begin a little but it may be wrong

 Tell me what you dont understand and i shall translate it for you

[fledarmus]

Start with what you know - we'll be happy to nudge you in the right direction if you start to get off track