What's Wrong with My Empirical Formula Calculation?

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The user attempted to calculate the empirical formula of a compound containing only carbon, hydrogen, and nitrogen based on combustion data. They calculated the masses of carbon and hydrogen from CO2 and H2O produced, then deduced the nitrogen content by subtracting these from the initial mass of the compound. However, the mistake was identified as failing to convert the masses from milligrams to grams, which led to incorrect molar calculations. This oversight resulted in an erroneous final empirical formula of C2H12N5. Correcting the unit conversion would resolve the calculation issue.
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So this problem was a part of my homework and I did the whole thing but apparently I got it wrong. Could someone point out what's wrong with my work?

Question:A compound contains only C, H, and N. Combustion of 35.0mg of the compound produces 33.5mg CO2 and 41.1mg H2O. What is the empirical formula of the compound.

Attempt: Found percent C in CO2: 2(16.00g)+12.01g=44.01g. 12.01g/44.01gx100%=27.29%C.
Found percent H in H2O:2(1.008g)+16.00g=18.016g. 2.016g/18.016x100%=11.9%H
Found mg of C: 27.29%x33.5mgCO2x1mgC/1mgCO2=9.14mgC
Found mg of H: 11.19%x41.1mgH2Ox1mgH/1mgH2O=4.60mgH

At this point I assumed that because the combusted compound contains only C, H, and N that I could just take the remaining 35-(9.14+4.60)=21.26 and that would be the mg of Nitrogen (If this is where the mistake is made how can I correct it?)

took a 100mg sample
H: 4.60mg/35.0mgx100%=13.1%H 13.1gHx1molH/1.008gH=12.996molH
C:9.14mg/35.0mgx100%=26.1%C 26.1gCx1molC/12.01gC=2.17molC
N:21.26mg/35.0mgx100%=75.0% 75.0gNx1molN/14.01gN=5.355molN

H:12.996/2.17=5.99=6 C: 2.17/2.17=1 N:5.355/2.17=2.47=2.5​
At this point because N turns out to be 2.5 I assume the empirical formula must be doubled and so I end with my final answer of C2H12N5 which is wrong, according to my teacher's work.

I hope all the work shown doesn't overwhelm people into not answering this.
 
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If there's a problem, I can't find it.
 
I was looking over it some more, and apparently I forgot to convert from mg to g and that's why the empirical formula is off.
 

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