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Topic: Equation with unknown compound is given, find that and product after hydrolysed  (Read 2112 times)

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Offline cloudy1290

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This question was from the test today, so I remembered as much as I could

A + O2 ---> CO2 + H2O
Given that A is CxHyOz, mass of CO2 is 110mg, mass of H2O is 40.5mg and mass of A is 50.5mg
and they said about result after products(B C D and E, I can't remember which one they mentioned) react with Tollen and Fehling. And 1 of them was added by Na to give H2
1. Find x,y,z and find A
2. Hydrolyze A and the products will be B+C (B has 2 moles, and C has 1 mol). Find B and C
3. Then C oxidize to D, D oxidize to E. Find D and E

my solution :
      CxHyOz + (x + y/4 - z/2)O2 ----> xCO2 + (y/2)H2O
      50.5/12x+y+16z                  =  110/44x =   40.5/9y
  =  101/12x+y+16z                   =  5/x        =   9/y

and from equation I solved and got x = 5y/9, y= 9z/2 then substituted y into x
so x : y : z = 5z/2 : 9z/2 : z = 5 : 9 : 1  so A is C5H9O2

I have searched and got 3 compounds : Cyclopentanolate, 4-Hydroxy-2-methylenebutyl and Hydroxypentyl. But I couldn't found the products after hydrolyzed
« Last Edit: June 22, 2019, 03:12:35 AM by cloudy1290 »

Offline AWK

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First of all, an organic compound containing only CHO should contain even number of hydrogen atoms.
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Offline cloudy1290

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First of all, an organic compound containing only CHO should contain even number of hydrogen atoms.

The masses I wrote were all correct. And I don't really have any idea.

Offline AWK

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Double your empirical formula and check oxygen
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Offline cloudy1290

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Double your empirical formula and check oxygen

it becomes C10H18O2, and its name is citronellic acid. But what do you mean "check oxygen"?

sorry i'm not fluent with english

Offline cloudy1290

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what do you mean "check oxygen"

Offline cloudy1290

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Double your empirical formula and check oxygen

Oh actually it was C5H9O2

Offline AWK

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and doubled empirical formula?
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Offline cloudy1290

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and doubled empirical formula?

then it will be C10H8O4, I'm still finding what it is

Offline AWK

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H8 or H18?
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Offline cloudy1290

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H8 or H18?

sorry mistyped, it's 18. Maybe Sebacic acid ?

Offline AWK

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Could you hydrolyze this compound?
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Offline cloudy1290

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Could you hydrolyze this compound?

I'm not good with Org Chem. But I think the question was wrong or my calculation method was wrong

Offline AWK

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It is rather impossible to determine a unique compound from your data. But from 2:1 ratio of hydrolysis products you can recognize for example ester of dicarboxylic acid.
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