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question relating mass spectra!

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Assi1993:
hi..i dont understand why propanone and propanal have a different mass spectra though they have the same relative molecular mass..i know that they have different structure but how does that effect the spectra????

waiting for the reply !!

Deadly_king:

--- Quote from: Assi1993 on October 05, 2010, 06:08:42 pm ---hi..i dont understand why propanone and propanal have a different mass spectra though they have the same relative molecular mass..i know that they have different structure but how does that effect the spectra????

waiting for the reply !!

--- End quote ---

Am sorry I need to run for now. So I won't be able to explain. Try this though:

http://www.chemguide.co.uk/analysis/masspec/fragment.html

http://www.chemguide.co.uk/analysis/masspecmenu.html

http://www.chemguide.co.uk/analysis/masspec/howitworks.html


If you still don't understand, let me know and i'll try as much as I can to clear your doubt :)

Assi1993:

--- Quote from: Deadly_king on October 05, 2010, 06:17:39 pm ---Am sorry I need to run for now. So I won't be able to explain. Try this though:

http://www.chemguide.co.uk/analysis/masspec/fragment.html

http://www.chemguide.co.uk/analysis/masspecmenu.html

http://www.chemguide.co.uk/analysis/masspec/howitworks.html


If you still don't understand, let me know and i'll try as much as I can to clear your doubt :)

--- End quote ---


umm thanks but.....i still didnt get the answer 2 my question :(

Deadly_king:
Ok......i'll try to help.

First you need to draw the structural formula of both compounds :

Propanone :CH3COCH3
Propanal : CH3CH2COH

Now we can determine the ions that will be produced during mass spectrometry.

For propanone : CH3+, CH3CO+ and H+

For propanal : CH3+, CH3CH2+, CH3CH2CO+ and H+

NOTE : The bonds in C=O does not break since they are very strong bonds.

Since the ions formed are different, their mass spectra will surely be different  ;)

Propanone and propanal may have the same relative molecular mass but the ions produced vary since their structure are different.

Hope it helps :)

Assi1993:

--- Quote from: Deadly_king on October 06, 2010, 06:26:22 am ---Ok......i'll try to help.

First you need to draw the structural formula of both compounds :

Propanone :CH3COCH3
Propanal : CH3CH2COH

Now we can determine the ions that will be produced during mass spectrometry.

For propanone : CH3+, CH3CO+ and H+

For propanal : CH3+, CH3CH2+, CH3CH2CO+ and H+

NOTE : The bonds in C=O does not break since they are very strong bonds.

Since the ions formed are different, their mass spectra will surely be different  ;)

Propanone and propanal may have the same relative molecular mass but the ions produced vary since their structure are different.

Hope it helps :)

--- End quote ---

ohh !! Thankss!........that helped :) may God bless u :D

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