I love science but one thing has always bugged me about chemistry. How in the world is it even possible for Oxygen to have an atomic weight of 15.9994 which is LESS than 16? Every other element has a weight equal to its number of protons and neutrons. (Or more if it is an isotope.) Is there some rare form of Oxygen (O 15) where it actually has one less neutron and is a lighter isotope? This is the only possible explanation I can come up with. I realize that Hydrogen (Protium) has only a proton and is missing its neutron. (Then there are the 2 heaver forms, Duterium and Tritium.) But other than Hydrogen there are NO other examples in the whole periodic table where there is a lighter isotope (missing a neutron) other than that. If this is NOT the reason why Oxygen has a weight less than 16.0000 please tell me WHY is does? Thank you very much.
2007-10-01 10:55:01 · 3 answers · asked by Becky 3 in Science & Mathematics ➔ Chemistry
An excellent question Becky. (I gave you a star.) You actually hit the nail on the head and answered your own question. Go to Wikipedia and you will see that there are 17 isotopes of Oxygen.
http://en.wikipedia.org/wiki/Oxygen
They range from 12.03 - 28.06 in atomic masses. Oxygen 15 is even used in Positron Emission Tomography. (PET Scans) The STABLE isotopes are 16,17 and 18. Steve's answer is wrong...the 15.9994 is based on ALL the isotopes and therefore has a number LESS than 16. The mystery is solved. You can now sleep at night. ;-)
2007-10-01 11:31:00 · answer #1 · answered by Smart Dude 6 · 2⤊ 1⤋
Most of oxygen is O-16. There is a few percent each of O-17 and O-18. The average of these isotopes is 15.9994. But this is because in recent years, the International Union of Pure & Applied Chemistry has decided that the atomic weights are to be based on carbon-12 = 12.000...... If you insist on that, then you come up with some weird results.
2007-10-01 11:09:08 · answer #2 · answered by steve_geo1 7 · 1⤊ 3⤋
a million mole ethanoic acid is created from 2 moles of carbon,2 moles(diatomic) of hydrogen,a million mole of oxygen basically upload their molecular weights withy no of moles so which you get w=2x12+2x2+1x32=60 grams 32=molecular wt of oxygen=atomic weightxatomicity(2) 2=molecular weight of H2=1x2(diatomic)=2
2016-10-10 03:11:09 · answer #3 · answered by ? 4 · 0⤊ 0⤋