brain fart

[st012m]

Help guys! cant remember how to get the empirical when its combustion

0.6943g of Terephthalic acid was subjected to combustion analysis it produced 1.471g CO2 and 0.226g of H2O.What is its empirical formula?

I did try to convert to moles then divide by the smallest but just didnt look right when I finished.I want to see what steps you guys took.Thanks!

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[IWantSmile]

Help guys! cant remember how to get the empirical when its combustion

0.6943g of Terephthalic acid was subjected to combustion analysis it produced 1.471g CO2 and 0.226g of H2O.What is its empirical formula?

I did try to convert to moles then divide by the smallest but just didnt look right when I finished.I want to see what steps you guys took.Thanks!

I actually don't know; but I want to try. Hear it goes...

1) TA ( Terephthalic acid) is completely combust to form CO2 and H2O.
TA + O2 ----> CO2 + H2O

2) based on that information I would calculate the Carbon composition and Hydrogen composition.
1.47g CO2 X ( 12g C / 44g CO2) =0.4g C
0.226g H2O X ( 2g H/ 18g H2O ) = 0.025g H
0.6943g TA - ( 0.4g C ) - (0.025g H) = 0.2693g O

3) convert to mole ratio of C: H: O = 0.03 : 0.025: 0.0168

4) then divided by smallest one which I got ; C1.78 : H1.5 : O
so, C2H1.5O ( ???)

The empirical formula is C2H1.5O. Is it right answer? or did I completely missed? But credit for me since I tried...

 

[st012m]

ah thanks!

I think your right.Just need to multiply the C2H1.5O times 2 to get rid of the decimals(C4H3O2).But great job and tyvm 😀

 

[IWantSmile]

ah thanks!

I think your right.Just need to multiply the C2H1.5O times 2 to get rid of the decimals(C4H3O2).But great job and tyvm 😀

Aha. That Decimal I need to rid of.. . Thank you too.