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Chemistry Forums for Students => High School Chemistry Forum => Chemistry Olympiad and other competitions => Topic started by: yuheng_wu on December 17, 2020, 02:45:23 AM

Title: Flemish chemistry olympiad question
Post by: yuheng_wu on December 17, 2020, 02:45:23 AM
Given
- incomplete combustion of atom X gives the following:
- X + O2  :rarrow: 1,5 . 10-2 mols CO2 + 4,5 . 10-2 mols CO + 4,5 . 10-2 mols H2O

Question: which atom is x?
a/ C2H2
b/ C4H6
c/ C4H8
d/ C4H10

The answer is b, but how do you solve this question? How do you know/calculate which atom X is?

Title: Re: Flemish chemistry olympiad question
Post by: AWK on December 17, 2020, 02:50:35 AM
Hydrocarbon X !
Count moles of atoms C and H and find ratio
Title: Re: Flemish chemistry olympiad question
Post by: yuheng_wu on December 17, 2020, 03:01:52 AM
Quote from: AWK on December 17, 2020, 02:50:35 AM
Hydrocarbon X !
Count moles of atoms C and H and find ratio
I understand now, thanks a lot!
Title: Re: Flemish chemistry olympiad question
Post by: yuheng_wu on December 17, 2020, 03:06:49 AM
Quote from: AWK on December 17, 2020, 02:50:35 AM
Hydrocarbon X !
Count moles of atoms C and H and find ratio
And if it were a complete combustion of the hydrocarbon X, do you have to count the amounts of O2 as well in that situation? Or when do you have to consider the ratio of O2 as well?
Title: Re: Flemish chemistry olympiad question
Post by: AWK on December 17, 2020, 03:11:12 AM
You are not asking for anything related to oxygen, that is, the amount of oxygen needed for this reaction.