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Molecular formula/Mass spectrometry please help watch

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    Hi guys, I worked out how to get 4 oxygens but just stuck on working out the number of carbons and hydrogens in the molecular formula of F. Can someone please help?
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    54,2 % oxygen means there are four oxygen atoms as 118 x 54.2/100 = 64 = 4 oxygen atoms

    The relative mass is 118 and subtracting your four oxygen atoms (64) from this leaves 54

    Each carbon is 12 therefore 3 carbon atoms (36) would need 18 H atoms (clearly impossible)
    5 carbon atoms = 60 units - also impossible

    Therefore there are four carbon atoms (48) and 6 hydrogen atoms
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    (Original post by charco)
    54,2 % oxygen means there are four oxygen atoms as 118 x 54.2/100 = 64 = 4 oxygen atoms

    The relative mass is 118 and subtracting your four oxygen atoms (64) from this leaves 54

    Each carbon is 12 therefore 3 carbon atoms (36) would need 18 H atoms (clearly impossible)
    5 carbon atoms = 60 units - also impossible

    Therefore there are four carbon atoms (48) and 6 hydrogen atoms
    Thank you so much! But why is 3 carbon atoms and 18 hydrogens impossible? - 36 and 18 add up to 54 and there might be a structure that fit this?
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    (Original post by sienna2266)
    Thank you so much! But why is 3 carbon atoms and 18 hydrogens impossible? - 36 and 18 add up to 54 and there might be a structure that fit this?
    You're 'aving a laff!

    Carbon has a maximum valency of 4 and hydrogen 1, the most hydrogen atoms possible for 3 carbon atoms is 8.
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    (Original post by charco)
    You're 'aving a laff!

    Carbon has a maximum valency of 4 and hydrogen 1, the most hydrogen atoms possible for 3 carbon atoms is 8.
    Oh yeah! Lol sorry -blaming it on being tired
 
 
 
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