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In chemistry, the molar mass (M) (sometimes called molecular weight or formula weight, but see related quantities for usage) of a chemical compound is defined as the ratio between the mass and the amount of substance (measured in moles) of any sample of the compound. [1] The molar mass is a bulk, not molecular, property of a substance.
The interest stems from that accurate measurements of the unit cell volume, atomic weight and mass density of a pure crystalline solid provide a direct determination of the Avogadro constant. [3] The CODATA recommended value for the molar volume of silicon is 1.205 883 199 (60) × 10 −5 m 3 ⋅mol −1, with a relative standard uncertainty of ...
Reaction stoichiometry describes the 2:1:2 ratio of hydrogen, oxygen, and water molecules in the above equation. The molar ratio allows for conversion between moles of one substance and moles of another. For example, in the reaction 2 CH 3 OH + 3 O 2 → 2 CO 2 + 4 H 2 O. the amount of water that will be produced by the combustion of 0.27 moles ...
The terms "molecular mass", "molecular weight", and "molar mass" may be used interchangeably in less formal contexts where unit- and quantity-correctness is not needed. The molecular mass is more commonly used when referring to the mass of a single or specific well-defined molecule and less commonly than molecular weight when referring to a ...
At relatively low alc/vol, the alcohol percentage by weight is about 4/5 of the alc/vol (e.g., 3.2% ABW is about 4% alc/vol). [25] However, because of the miscibility of alcohol and water, the conversion factor is not constant but rather depends upon the concentration of alcohol. [citation needed]
Mass fraction can also be expressed, with a denominator of 100, as percentage by mass (in commercial contexts often called percentage by weight, abbreviated wt.% or % w/w; see mass versus weight). It is one way of expressing the composition of a mixture in a dimensionless size ; mole fraction (percentage by moles , mol%) and volume fraction ...
Alcohol measurements are units of measurement for determining amounts of beverage alcohol. Alcohol concentration in beverages is commonly expressed as alcohol by volume (ABV), ranging from less than 0.1% in fruit juices to up to 98% in rare cases of spirits. A "standard drink" is used globally to quantify alcohol intake, though its definition ...
For other countries, it may be easiest to convert to UK units. For example, in the United States one standard drink contains 14 grams ≈ 1.75 units of alcohol, and so a US standard drink takes the body about an hour and three-quarters to process. Blood alcohol content can more accurately be estimated by using Widmark's formula. [43]