× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
g
1
Home Q & A Board Science-Related Homework Help Chemistry (Moderator: Laser_3)
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 506 times
2 Replies

Related Topics

Replies
wrote...
#1
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...
#2
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      
Quick Reply
Bold
Italic
Underline
Strikethrough
Subscript
Superscript
Insert Math Equation
Font Name
Font Color
Align left
Center
Align right
Bullet list
Numbered list
Insert a horizontal rule
Insert a table
Insert a Quote
View source
Explore
Post your homework questions and get free online help from our incredible volunteers
  2097 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Related Images
  
 192
  
 304
  
 235
Your Opinion
Who's your favorite biologist?
Votes: 722
Previous poll results: Do you believe in global warming?