mtb_dpr
Badges: 0
Rep:
?
#1
Report Thread starter 2 years ago
#1
I have been trying to understand this idea of Relative Isotopic Mass but all I seem to get is the same old definition regarding the idea of its a comparison of the mass of 1/12th if the mass of a Carbon 12 atom etc etc... But this isn't really helping my understanding of it. Can anyone explain this concept in a slightly more elaborate way?
0
reply
Pigster
Badges: 19
Rep:
?
#2
Report 2 years ago
#2
How heavy is an atom?

Compared to what?

Something that has a mass of 1 g? Or compared to one atom of carbon with a mass number of 12?

It is no more complex than that. Stop trying to make it so.
0
reply
charco
Badges: 17
Rep:
?
#3
Report 2 years ago
#3
(Original post by mtb_dpr)
I have been trying to understand this idea of Relative Isotopic Mass but all I seem to get is the same old definition regarding the idea of its a comparison of the mass of 1/12th if the mass of a Carbon 12 atom etc etc... But this isn't really helping my understanding of it. Can anyone explain this concept in a slightly more elaborate way?
All measurements of any quantity are made relative to an agreed standard so that we can all communicate with each other.

If I say that I'm six foot tall, it makes no sense unless we all know and agree what one foot is.

The same goes for mass and metric measurements of distance and every possible thing.

So, if you want to measure the mass of an atom, you can do it relative to one atom of the isotope carbon 12, which is assigned a value of exactly 12.0000.

The value is then called the relative isotopic mass.

Carbon-12 is the current standard, but it hasn't always been. At different times in history both hydrogen and oxygen isotopes have been used.

The IUPAC agreed to use 12C about 70 years ago.
2
reply
tcameron
Badges: 16
Rep:
?
#4
Report 2 years ago
#4
(Original post by mtb_dpr)
I have been trying to understand this idea of Relative Isotopic Mass but all I seem to get is the same old definition regarding the idea of its a comparison of the mass of 1/12th if the mass of a Carbon 12 atom etc etc... But this isn't really helping my understanding of it. Can anyone explain this concept in a slightly more elaborate way?
Best way to explain this is that. An atom doesn't have a mass we can measure, so we compare them relative to a given mass. So the basis is carbon-12 and it's given mass is 12. From there any mass of atom is determined in relation to this given mass of 12 of carbon-12.
It's hard to explain even me now at uni the best thing is to try not to understand it because many concepts in chemistry can't be explained easily unless you're at a very high level. I.e degree standard.
1
reply
mtb_dpr
Badges: 0
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by charco)
All measurements of any quantity are made relative to an agreed standard so that we can all communicate with each other.

If I say that I'm six foot tall, it makes no sense unless we all know and agree what one foot is.

The same goes for mass and metric measurements of distance and every possible thing.

So, if you want to measure the mass of an atom, you can do it relative to one atom of the isotope carbon 12, which is assigned a value of exactly 12.0000.

The value is then called the relative isotopic mass.

Carbon-12 is the current standard, but it hasn't always been. At different times in history both hydrogen and oxygen isotopes have been used.

The IUPAC agreed to use 12C about 70 years ago.
Thank you for the help on this, the way you explained it really helped with understanding what this concept is all about, rather than just being told a definition and expected to understand it from that.
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

University open days

  • University of Surrey
    All subjects except Veterinary Medicine and Guildford School of Acting Undergraduate
    Wed, 20 Nov '19
  • The University of Law
    Solicitor Series: Discover Your Type of Law - LPC and GDL - Birmingham campus Postgraduate
    Wed, 20 Nov '19
  • Buckinghamshire New University
    Postgraduate and professional courses Postgraduate
    Wed, 20 Nov '19

Have you made up your mind on your five uni choices? (November update)

Yes I know where I'm applying (47)
75.81%
No I haven't decided yet (9)
14.52%
Yes but I might change my mind (6)
9.68%

Watched Threads

View All