The molar mass of hydrogen: heavy and light

click fraud protection

The lightest of the chemical elements, mandatory component of organic compounds, a necessary part of the molecules of life - water - and it's all about hydrogen.The name translated into Russian with the help of conversion of parts of the Greek word - "giving birth to water."Hydrogen as a gas - a substance rather capricious and dangerous (inflammable!).A hydrogen in atomic form - is very active and has reducing properties.Therefore, the chemical zadachnik student may be asked to determine what is the molar mass of hydrogen.This question can stump even the chemistry rusty adults.

clarifies what is meant

The concept of "hydrogen" from a logical point of view, ambiguous.It can mean hydrogen atoms, and the corresponding gas existing in the molecular form.In the second case - a combination of two atoms.Rather, the notion of "the molar mass of hydrogen" refers to the gas for individual atoms rather apply the concept of atomic mass.But in free form hydrogen may exist, especially when some of the physico-chemical processes.And this substance has a mole weight.So every time you meet the challenges specify exactly what is meant.

free atoms

If you mean an atom, the molar mass of hydrogen is equal to one gram per mole.It can be converted into kilograms per mole to comply with the SI, for this you just need to multiply the 1 in 10 to the minus third degree.Although these data are not entirely accurate, because the atomic weight - values ​​are not integers and fractions.

How hard!

But be careful - if you solve the problem in physics textbook, you can be faced with severe forms of hydrogen, which have different molar mass.The most common is called hydrogen against, and it weighs one gram mole, but there is also deuterium (2 g per mole), and tritium (3 g per mole).Deuterium in very small amounts (less than 0.2%) is found in the world, and almost all tritium does not occur, but it is easy to obtain in nuclear reactions.In the process of solving the real problems of physics and chemistry do not differentiate, so if you are preparing for a career in the natural sciences must be prepared to determine the molar mass of hydrogen in such non-standard situations.

calculations for molecular form

If the problem refers to the gas, you will need to multiply the atomic weight of hydrogen to two and one attributed grams per mole.Amu and grams per mole equal numerically, but the first is used more in the discussion of physics and the properties of elements, and the second - in solving practical problems in chemistry.But here you can catch and ask the mass of heavy hydrogen.By the way, be careful, sometimes from you will be expected not multiply 2 or 3 in two.There are hybrid forms, such as deuterium and tritium (hydrogen molar mass at the same time is 2 + 3 = 5), or anti-deuterium (3), or tritium against (4).Therefore, logically and folding, rather than multiply, not to be mistaken with heavy molecules.

Interestingly, the water, which includes heavy hydrogen, also called heavy.Problems with its yield of heavy hydrogen can be difficult, and for this purpose may have to calculate what is the molar mass of hydrogen in your particular situation.