please help me..The stimulant in coffee and tea is caffeine, a substance of molar mass 194g/mol.?

Question

when 0.376g of caffeine was burned, 0.682g carbon dioxide, 0.174g of water and 0.110g of nitrogen were formed. determine teh empirical and molecular formulas of caffeine..
im realy confuse.

Answer 1

Let Caffeine be CxHyOzNs where x,y,z and s have to be determined.

Moles of Caffeine = 0.376/194

Moles of N2 = 0.11/28

Thus 0.376*s/(194*2) = 0.11/28

So, s = 4

Now, Moles of CO2 released = 0.376x/194 = 0.682/44

So, x = 8

Moles of H2O = 0.376*y/388 = 0.174/18

So, y = 10

Mass of O = 194-(4*14+8*12+10) = 32 g

So, z = 2

Molecular formula is C8H10O2N4

and empirical formula is C4H5ON2