Chemistry Forum

Hi guys, I have this problem:
An organic compound, which contains C, H, O and Cl gave the following results: 0.16g produce from combustion 0.265g of CO₂ and 0.0325g of H₂O. If I melt 0.215g of the compound in water with the addiction of AgNO₃ I obtain 0.236g of AgCl. Find the molecular formula of the compound. Molar mass is 130.5g/mol.

I obtained the mass of oxygen with the following operation:
(0.0325 + 0.265) - 0.16g from the reaction of combustion
I calculate moles of oxygen, hydrogen, carbon from CO₂ and Cl from the salt, but the molecular formula that I found doesn’t march with the text result.
Can you help me ?
Thank you in advance.

The calculation for oxygen is wrong, because the molecule also contain oxygen.
The masses of CO₂ and H₂O correspond to C and H. Calculate the moles of it and do a ratio to unbroken numbers.
The mass of silverchloride correspond to the mass of Chlorine. Do also mole ratio.
If you have C, H and Cl subtract it from the molar mass of the compound you get molar mass of oxygen.

ChenBeier wrote: ↑Sun Jan 28, 2024 6:12 am The calculation for oxygen is wrong, because the molecule also contain oxygen.
The masses of CO₂ and H₂O correspond to C and H. Calculate the moles of it and do a ratio to unbroken numbers.
The mass of silverchloride correspond to the mass of Chlorine. Do also mole ratio.
If you have C, H and Cl subtract it from the molar mass of the compound you get molar mass of oxygen.

Right, thank you very much

What is your result?

sottozer0 wrote: ↑Sun Jan 28, 2024 8:24 am

ChenBeier wrote: ↑Sun Jan 28, 2024 6:12 am The calculation for oxygen is wrong, because the molecule also contain oxygen.
The masses of CO₂ and H₂O correspond to C and H. Calculate the moles of it and do a ratio to unbroken numbers.
The mass of silverchloride correspond to the mass of Chlorine. Do also mole ratio.
If you have C, H and Cl subtract it from the molar mass of the compound you get molar mass of oxygen.

Right, thank you very much

Can you give me the results to see if the answer is the same as mine?

Why not give yours first?