Why is this answer right - chem? Watch

FutureMissMRCS
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#1
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#1
The answer is A and I don't understand why is statement 2 true. I drew out the structure and fragmented it and Ch3ch2 gives you an mr of 29 how did they get an m/z of 28?
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charco
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#2
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If you strip off the two ethyl groups, you are left with a carbonyl fragment (ion), which has a m/z = 28
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FutureMissMRCS
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(Original post by charco)
If you strip off the two ethyl groups, you are left with a carbonyl fragment (ion), which has a m/z = 28
I thought in mass spectra when you fragment the compound you can only break one bond at a time-not 2-is that not the case then?
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charco
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You can just keep breaking bonds:

CH3CH2COCH2CH3 ==> CH3CH2COCH2+ + CH3

CH3CH2COCH2+ ==> CH3CH2CO+ + CH2

CH3CH2CO+ ==> CH2CO+ + CH3

CH2CO+ ==> CO+ + CH2

... and many other possibilities
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FutureMissMRCS
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(Original post by charco)
You can just keep breaking bonds:

CH3CH2COCH2CH3 ==> CH3CH2COCH2+ + CH3

CH3CH2COCH2+ ==> CH3CH2CO+ + CH2

CH3CH2CO+ ==> CH2CO+ + CH3

CH2CO+ ==> CO+ + CH2

... and many other possibilities
Thank you for explaining
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