× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
1
New Topic  
fire117 fire117
wrote...
Posts: 42
Rep: 0 0
12 years ago
the atomic mass of carbon is 12 and that of hydrogen is 1. why ? moreover the mass of hydrogen is not exactly 1 its 1.099. why?
Read 507 times
2 Replies

Related Topics

Replies
wrote...
12 years ago
1 u (atomic mass unit) is exactly 1/12 the mass of an carbon atom (12C6 - an atom with 6 proton and 6 neutron)
so, it is clear that a carbon atom will have a mass of 12u

But a proton and a neutron doesn't have the same weight, so 1u is not exactly the mass of a neutron or a proton

A hydrogen has only 1 proton, so it mass is about 1u, but since proton is a little bit heavier, it is 1.099u
wrote...
12 years ago
The atomic mass of an element is the average protons + neutrons of all of the isotopes of that element.  The mass of hydrogen is slightly higher than 1 because there are three isotopes (protium, deuterium, and tritium).  The atomic mass of carbon is 12 because the most common isotope of carbon is C12.  That is 6 protons and 6 neutrons.
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  2063 People Browsing
Related Images
  
 1889
  
 400
  
 349
Your Opinion
Which of the following is the best resource to supplement your studies:
Votes: 388