Danyal124
Badges: 9
Rep:
?
#1
Report Thread starter 1 month ago
#1
Help!! Test tomorrow and I’m stuckName:  23C12C29-8444-456F-91C7-D95A1EC3435D.jpeg
Views: 12
Size:  125.3 KBName:  A2E88528-6BEE-4DCD-B8A0-DD942C7AF86B.jpeg
Views: 12
Size:  73.4 KB on the second question
Last edited by Danyal124; 1 month ago
0
reply
ram8_
Badges: 13
Rep:
?
#2
Report 1 month ago
#2
(Original post by Danyal124)
Help!! Test tomorrow and I’m stuckName:  23C12C29-8444-456F-91C7-D95A1EC3435D.jpeg
Views: 12
Size:  125.3 KBName:  A2E88528-6BEE-4DCD-B8A0-DD942C7AF86B.jpeg
Views: 12
Size:  73.4 KB 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?
0
reply
golgiapparatus31
Badges: 13
Rep:
?
#3
Report 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
0
reply
ram8_
Badges: 13
Rep:
?
#4
Report 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?
0
reply
golgiapparatus31
Badges: 13
Rep:
?
#5
Report 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
0
reply
user342
Badges: 1
Rep:
?
#6
Report 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?
0
reply
ram8_
Badges: 13
Rep:
?
#7
Report 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)?
0
reply
golgiapparatus31
Badges: 13
Rep:
?
#8
Report 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.
0
reply
golgiapparatus31
Badges: 13
Rep:
?
#9
Report 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
0
reply
user342
Badges: 1
Rep:
?
#10
Report 1 month ago
#10
(Original post by golgiapparatus31)
They are part (a) and (c) I believe
Do you have a picture of part b?
0
reply
golgiapparatus31
Badges: 13
Rep:
?
#11
Report 1 month ago
#11
(Original post by user342)
Do you have a picture of part b?
Nope
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Should there be a new university admissions system that ditches predicted grades?

No, I think predicted grades should still be used to make offers (714)
33.85%
Yes, I like the idea of applying to uni after I received my grades (PQA) (903)
42.82%
Yes, I like the idea of receiving offers only after I receive my grades (PQO) (399)
18.92%
I think there is a better option than the ones suggested (let us know in the thread!) (93)
4.41%

Watched Threads

View All
Latest
My Feed