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This is the answer to chapter 13 problem number six from the smith organic chemistry textbook.
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And this problem is asking us to consider putting 2 -4 trimethylpentane into a mass spectrometer.
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And we are told that the base peak occurs at a mass -to -charge number of 57.
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And we are asked to draw what that 57 represents and to talk about why that's the most abundant ion.
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And so you could approach this problem really from two directions.
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What i did first was i considered the ion, the base peak at 57, and i thought about so this molecule only has carbons and hydrogens in it.
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And so what combination of carbons and hydrogens can get me to 57? and so c4h9 adds up to 57.
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As you can see here, i drew the math out in green.
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And then going back and looking at our original molecule, is there a bond that can break that will result in an ion with a formula of c480? h9.
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And there is, and it's this bond.
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I've crossed it in red to show that it's breaking, and you can see that will give us four carbons, nine hydrogens, and a positive charge on that fragment...