Mass Spectrometry question help Watch

-inspired-
Badges: 10
Rep:
?
#1
Report Thread starter 3 years ago
#1
Hi,

I'm studying AS OCR chemistry and I'm not sure how to answer one of the questions on Mass Spectrometry.

Question: A sample of Hydrogen containing the Isotopes Hydrogen-1, Hydrogen-2 and Hydrogen-3 was analysed in a Mass Spectrometer. How many peaks corresponding to H2+ would be expected?

The answer is 5 but I have no idea how/why that is the answer.

Any help would be appreciated
0
reply
charco
Badges: 17
Rep:
?
#2
Report 3 years ago
#2
(Original post by -inspired-)
Hi,

I'm studying AS OCR chemistry and I'm not sure how to answer one of the questions on Mass Spectrometry.

Question: A sample of Hydrogen containing the Isotopes Hydrogen-1, Hydrogen-2 and Hydrogen-3 was analysed in a Mass Spectrometer. How many peaks corresponding to H2+ would be expected?

The answer is 5 but I have no idea how/why that is the answer.

Any help would be appreciated
In a molecule there are two atoms and either of the atoms can be 1H, 2H or 3H

How many possible combinations are there?
0
reply
-inspired-
Badges: 10
Rep:
?
#3
Report Thread starter 3 years ago
#3
(Original post by charco)
In a molecule there are two atoms and either of the atoms can be 1H, 2H or 3H

How many possible combinations are there?
I thought of that, but wouldn't that only provide three combinations?

1H + 2H
1H + 3H
2H + 3H

Unless I'm missing something (which is highly likely!)
0
reply
charco
Badges: 17
Rep:
?
#4
Report 3 years ago
#4
(Original post by -inspired-)
I thought of that, but wouldn't that only provide three combinations?

1H + 2H
1H + 3H
2H + 3H

Unless I'm missing something (which is highly likely!)
What about 1H + 1H, 2H + 2H and 3H + 3H?
0
reply
-inspired-
Badges: 10
Rep:
?
#5
Report Thread starter 3 years ago
#5
(Original post by charco)
What about 1H + 1H, 2H + 2H and 3H + 3H?
Ah I knew I was forgetting some combinations! Wouldn't that make six peaks though?
0
reply
Pigster
Badges: 17
Rep:
?
#6
Report 3 years ago
#6
What would the m/z values of the six peaks be?
0
reply
-inspired-
Badges: 10
Rep:
?
#7
Report Thread starter 3 years ago
#7
(Original post by Pigster)
What would the m/z values of the six peaks be?
Oh I see, so the 1H + 3H possibility has the same m/z value as 2H + 2H so wouldn't form it's own peak so there would be five. Thank you so much both of you
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
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

University open days

  • Manchester Metropolitan University
    Undergraduate Open Day Undergraduate
    Wed, 19 Jun '19
  • University of West London
    Undergraduate Open Day - West London Campus Undergraduate
    Wed, 19 Jun '19
  • University of Warwick
    Undergraduate Open Day Undergraduate
    Fri, 21 Jun '19

How did your AQA A-level Biology Paper 2 go?

Loved the paper - Feeling positive (425)
18.66%
The paper was reasonable (1076)
47.23%
Not feeling great about that exam... (506)
22.21%
It was TERRIBLE (271)
11.9%

Watched Threads

View All