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#1
Help!! Test tomorrow and I’m stuck on the second question
Last edited by Danyal124; 1 month ago
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1 month ago
#2
(Original post by Danyal124)
Help!! Test tomorrow and I’m stuck on the second question
Well we need part (a) in order to obtain an answer.. or is my screen bugged and I can't see it?
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1 month ago
#3
(Original post by ram8_)
Well we need part (a) in order to obtain an answer.. or is my screen bugged and I can't see it?
CO2H has MR = 12 + 32 + 1 = 45

Rest of molecule has mass 88 - 45 = 43

43 is C3H7

so C3H7CO2H is the molecule, the MF is C4H8O2
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1 month ago
#4
(Original post by golgiapparatus31)
CO2H has MR = 12 + 32 + 1 = 45

Rest of molecule has mass 88 - 45 = 43

43 is C3H7

so C3H7CO2H is the molecule, the MF is C4H8O2
Ah I see. But I presume that part (a) would give us an empirical formula and we can see the ratio between the molecular mass and the empirical formula mass to calculate the molecular formula, which I think would have been easier?
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1 month ago
#5
(Original post by ram8_)
Ah I see. But I presume that part (a) would give us an empirical formula and we can see the ratio between the molecular mass and the empirical formula mass to calculate the molecular formula, which I think would have been easier?
Part (a) [1 in the picture] asks for the Mr which they wrote as 88.

Part (b) [2 in the picture] asks for the molecular formula which can be worked out from the mass spectrum.

They didn't give the empirical formula
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1 month ago
#6
(Original post by golgiapparatus31)
Part (a) [1 in the picture] asks for the Mr which they wrote as 88.

Part (b) [2 in the picture] asks for the molecular formula which can be worked out from the mass spectrum.

They didn't give the empirical formula
I thought 2 in the picture was part c?
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1 month ago
#7
(Original post by golgiapparatus31)
Part (a) [1 in the picture] asks for the Mr which they wrote as 88.

Part (b) [2 in the picture] asks for the molecular formula which can be worked out from the mass spectrum.

They didn't give the empirical formula
Aren't the questions in the pictures part (b) and (c)?
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1 month ago
#8
(Original post by user342)
I thought 2 in the picture was part c?
Sorry. I didn't see that as it's nearly cut off. You are right. Then the empirical formula must be used along with the Mr.
My method in post 3 gets zero marks in the exam.
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1 month ago
#9
(Original post by ram8_)
Aren't the questions in the pictures part (b) and (c)?
They are part (a) and (c) I believe
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1 month ago
#10
(Original post by golgiapparatus31)
They are part (a) and (c) I believe
Do you have a picture of part b?
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1 month ago
#11
(Original post by user342)
Do you have a picture of part b?
Nope
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