Instant · Precise · Universal
34 units available
6 categories total
To convert u to kg: multiply by 1.6605390666 × 10⁻²⁷. To convert u to MeV/c²: multiply by 931.494.
1 u = 1.6605390666 × 10⁻²⁷ kg = 1/Nₐ grams ≈ 931.494 MeV/c².
For example, 1 Atomic Mass Unit (u) = 0.9914095198 Neutron Mass (mn).
| Atomic Mass Unit (u) | Neutron Mass (mn) |
|---|---|
| 0.1 | 0.09914095198 |
| 0.5 | 0.4957047599 |
| 1 | 0.9914095198 |
| 2 | 1.98281904 |
| 5 | 4.957047599 |
| 10 | 9.914095198 |
| 25 | 24.785238 |
| 50 | 49.57047599 |
| 100 | 99.14095198 |
| 500 | 495.7047599 |
| 1000 | 991.4095198 |
The atomic mass unit (unified) is defined as 1/12 the mass of a carbon-12 atom, approximately 1.661 × 10⁻²⁷ kilograms.
1 u = 1.6605390666 × 10⁻²⁷ kg = 1/Nₐ grams ≈ 931.494 MeV/c².
To convert u to kg: multiply by 1.6605390666 × 10⁻²⁷. To convert u to MeV/c²: multiply by 931.494.
Molecular weight calculations, mass spectrometry data interpretation, and chemical stoichiometry.
A proton has a mass of ~1.007 u, a neutron ~1.009 u. The discrepancy from 1.000 reflects nuclear binding energy.
Confusing 'amu' (the old, obsolete term) with 'u' (the unified standard). Also, forgetting that 1 u ≠ 1 gram.
Think of u as 'approximately the mass of one proton or neutron.' Carbon-12 = 12 u exactly (by definition).
The neutron mass is the rest mass of a neutron, approximately 1.675 × 10⁻²⁷ kilograms, slightly heavier than a proton.
mn = mp + 1.293 MeV/c². About 0.14% heavier than a proton.
To convert neutron masses to kg: multiply by 1.67492749804 × 10⁻²⁷.
Nuclear reactor design, neutron radiography, and neutron activation analysis for material composition.
A free neutron decays into a proton, electron, and antineutrino in about 14.7 minutes. Inside a nucleus, it can be stable for billions of years.
Assuming neutrons and protons have exactly the same mass — the neutron is 0.14% heavier, which is critical for nuclear stability.
The mn > mp mass difference allows neutron beta decay (n → p + e⁻ + ν̄ₑ). Without it, atomic nuclei as we know them wouldn't exist.



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