Convert Atomic Mass Unit (u) to Quarter (US) (qr (US)) instantly.
About these units
Atomic Mass Unit (u)
The atomic mass unit (u) is defined as exactly 1/12 the mass of a neutral carbon-12 atom, which makes it approximately 1.66053906660 × 10⁻²⁷ kilograms. This definition allows scientists to express atomic and molecular masses in a convenient, intuitive scale that aligns with the structure of the periodic table. By anchoring the unit to carbon-12, chemists and physicists gained a universal reference point that harmonizes molecular weight, relative isotopic abundance, and mass spectroscopy results. The atomic mass unit effectively normalizes the complexity of atomic masses into whole-number or near-whole-number values for most nuclei. In chemistry, u is indispensable for calculating molar masses, reaction stoichiometry, and isotopic compositions. It is also used across nuclear physics, astrophysics, and biophysics, demonstrating the universality of atomic-scale measurement.
Quarter (US) (qr (US))
The US quarter equals 25 pounds, serving as a smaller commercial subdivision of the hundredweight. It was used for pricing agricultural goods, livestock feed, and some industrial materials. Its convenience arises from the fact that four quarters make a hundredweight, simplifying scaling between small and medium quantities. Today it is mostly of historical interest, but agricultural economists still encounter it when analyzing archival data.