Table of Contents
- 1 Is the atomic mass of oxygen is 16?
- 2 Why do we take 1/12 mass of a carbon atom instead of the mass of the whole element of carbon?
- 3 Where is oxygen 16 found?
- 4 Why is carbon-12 considered to be a standard unit?
- 5 Why is c12 chosen as standard?
- 6 What value of oxygen is 16?
- 7 Is the mass of a carbon 12 atom equal to 1/12th?
- 8 Why is the atomic mass of oxygen-17 and oxygen-18 different?
Is the atomic mass of oxygen is 16?
Oxygen-16 atom is the stable isotope of oxygen with relative atomic mass 15.994914.
Why is the atomic mass of oxygen 16?
Atomic mass of an element is the relative mass of its atom as compared with the mass of a carbon-12 atom taken as 12 units. Hence, atomic mass of oxygen is 16 u means that one atom of oxygen is 16 times heavier than 1/12 of a carbon-12 atom.
Why do we take 1/12 mass of a carbon atom instead of the mass of the whole element of carbon?
Even hydrogen has 1.008 g and this is not useful for measuring atomic mass especially if the mass is a whole number . This is used because of its accuracy . The atomic mass unit should be accurate and precise . No other number is better than 1.00 g and hence carbon is chosen and 1/12 th of carbon is chosen .
Why did carbon-12 replace oxygen 16?
Answer Expert Verified Earlier Oxygen was used as the reference for mass measurements. Carbon was being increasingly used as a reference in mass spectroscopy. Choosing pure C-12 isotope as the reference made the changes in the masses of elements and compounds to be small. Choosing oxygen needed making bigger changes.
Where is oxygen 16 found?
occurs in three isotopes: 16O (99.763 percent), 17O (0.0375 percent), and 18O (0.1995 percent). Oxygen is found in all organisms and many minerals, including the aragonite and calcite that make up the shells of marine microfossils such as foraminifera.
What does oxygen 16 grams mean?
One mole of atoms of oxygen has a mass of 16 g, as 16 is the atomic weight of oxygen, and contains 6.02 X 1023 atoms of oxygen.
Why is carbon-12 considered to be a standard unit?
Carbon-12 is the standard while measuring the atomic masses. Because no other nuclides other than carbon-12 have exactly whole-number masses in this scale.
Why is carbon-12 used as a reference?
Chemists assigned natural oxygen — which is a mixture of 16O, 17O and 18O — a mass of exactly 16. 12C would be assigned a mass of exactly 12. This placed the new scale approximately midway between the two old, oxygen-based scales. Hence, carbon-12 is used as the standard reference for measuring atomic mass.
Why is c12 chosen as standard?
Why was oxygen not considered as a standard for atomic mass?
Oxygen was chosen because it forms chemical compounds with many other elements, simplifying determination of their atomic weights. Sixteen was chosen because it was the lowest whole number that could be assigned to oxygen and still have an atomic weight for hydrogen that was not less than 1.
What value of oxygen is 16?
Oxygen-16 (16O) is a stable isotope of oxygen, having 8 neutrons and 8 protons in its nucleus. It has a mass of 15.99491461956 u. Oxygen-16 is the most abundant isotope of oxygen and accounts for 99.762\% of oxygen’s natural abundance….Oxygen-16.
| General | |
|---|---|
| Neutrons | 8 |
| Nuclide data | |
| Natural abundance | 99.76\% |
| Half-life | stable |
What is the atomic mass of oxygen 18?
17.999160
CHEBI:33815 – oxygen-18 atom
| ChEBI Name | oxygen-18 atom |
|---|---|
| ChEBI ID | CHEBI:33815 |
| Definition | The stable isotope of oxygen with relative atomic mass 17.999160 and 0.205 atom percent natural abundance. |
| Stars | This entity has been manually annotated by the ChEBI Team. |
| Supplier Information | No supplier information found for this compound. |
Is the mass of a carbon 12 atom equal to 1/12th?
This is not correct. The unified atomic mass unit u is defined as 1/12th the mass of a carbon-12 atom. The atomic mass unit (amu) is defined as 1/16th the mass of the oxigen-16 isotope (physics) or 1/16th of the (average) mass of an oxigen atom (chemists).
What is the mass of a carbon 12 atom in Amu?
An atomic unit of mass is defined as accurately 1/12 the mass of a carbon-12 atom. The carbon-12 atom has six neutrons and six protons in its nucleus. The atomic unit mass is symbolized as AMU or amu. 1 AMU = Average of the proton rest mass and the neutron rest mass.
Why is the atomic mass of oxygen-17 and oxygen-18 different?
However, because oxygen-17 and oxygen-18 are also present in natural oxygen this led to two different tables of atomic mass. The unified scale based on carbon-12, X 12 X 2 2 12 C, met the physicists’ need to base the scale on a pure isotope, while being numerically close to the chemists’ scale.
Why is the mass of 12 nucleons 1/12 of an atom?
The carbon-12 isotope which has 12 nucleons is the standard mass for defining the unified atomic mass unit to be 1/12 of that atom’s rest mass. WHY? Chemists and physicists wanted a common (agreed upon) unit that approximated the average mass of a nucleon.