Atomic mass unit (AMU) ```Name: mark h chu Status: N/A Age: N/A Location: N/A Country: N/A Date: 1999 ``` Question: What's the difference between AMU and gram atomic mass? Thanks. Replies: The atomic mass unit, or amu, is defined so that the mass of 1 mole of carbon atoms is exactly 12.000000000 amu. The amu has the added convenience of being equal to units of grams per mole; 1 amu = 1 gram/mole. So, one mole of C12 weighs 12.00000000 grams. I believe that this is strictly true....someone correct me if I am mistaken. -dr topper The atomic mass unit (amu) is defined to be exactly 1/12 of the mass of a C-12 atom (Not a mole of carbon atoms...) Therefore 1 C-12 atom has a mass of exactly 12.00000000 amu. Also, therefore, 1 amu is a very small unit of mass - specifically 1amu = 1.66053X10^-24 grams. 1.00 mole of C-12 atoms has a mass of 12.0000000 grams! Dr. Brown P.S. Most college level general text books do not refer specifically to gram atomic weight. I got the above information from Brown, LeMay and Bursten - "Chemistry- The Central Science" (That Brown is not me.) Click here to return to the Chemistry Archives

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