## Oxygen Amu

I Oxygen Classes AMU.B.TECH ( 2021-21 ) Rank 07 Rank 110. Bank Medical Road, Aligarh. I Oxygen Classes. Name: Oxygen Symbol: O Atomic Number: 8 Atomic Mass: 15.9994 amu Melting Point:-218.4 °C (54.750008 K, -361.12 °F) Boiling Point:-183.0 °C (90.15 K, -297.4 °F) Number of Protons/Electrons: 8 Number of Neutrons: 8 Classification: Non-metal Crystal Structure: Cubic Density @ 293 K: 1.429 g/cm 3 Color: colorless Atomic Structure.

### Oxygen is composed of three isotopes 16/8 O (15.995 u), 17/8 O (16.999 u) and 18/8 O (17.999 u). One of these isotopes, 17/8 O, comprises of 0.037% of oxygen. What is the percentage abundance of the other two isotopes, using the average atomic mass of 15.9994 u. The abundance of ${'}_{8}^{16} ' O '$ is 99.762 %, and the abundance of ${'}_{8}^{18} ' O '$ is 0.201 %.

Assume you have 100 000 atoms of O. Then you have 37 atoms of ${'}_{8}^{17} ' O '$ and 99 963 atoms of the other isotopes.

Let x = the number of atoms of ${'}_{8}^{16} ' O '$. Then the number of atoms of ${'}_{8}^{18} ' O '$ = 99 963 - x

The total mass of 100 000 atoms is

x × 15.995 u + (99 963 – x) × 17.999 u + 37 × 16.999 u = 100 000 × 15.9994 u 15.995 x + 1 799 234.037 – 17.999 x + 628.963 = 1 599 940

### Mass Of Oxygen Amu

2.004 x = 199 123

x = 199 123/2.004 = 99 762

So there are 99 762 atoms of ${'}_{8}^{16} ' O '$ or 99.762 %.

### Oxygen's Amu

The number of ${'}_{8}^{18} ' O '$ atoms is 99 963 – 99 762 = 201 atoms or 0.201 %.

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