The lightest of the chemical elementsan essential component of organic matter, a necessary part of the molecules of life — water — and this is all about hydrogen. His very name was translated into Russian by converting parts of the word Greek - "who gives birth to water." Hydrogen-like gas is a rather capricious and dangerous substance (ignited!). And hydrogen in atomic form is very active and has reducing properties. Therefore, students may be asked to determine what the molar mass of hydrogen is in chemical problem books. This question can stump even the forgotten chemistry of adults.
Specify what is meant
The concept of "hydrogen" from a logical point of viewambiguous. It can mean both atoms of hydrogen, and the corresponding gas existing in a molecular form. In the second case, it is a combination of two atoms. Most likely, the term “molar mass of hydrogen” refers to gas, since the concept of atomic mass is used for individual atoms. But in the free form hydrogen may exist, especially in certain physicochemical processes. And the mole of this substance has a mass. Therefore, each time you solve a problem, specify what exactly is meant.
Free atom
If an atom is meant, then the molar masshydrogen is one gram per mole. It can be converted into kilograms per mole in order to comply with the requirements of the SI, to do this, simply multiply 1 by 10 to minus the third degree. Although this data will not be entirely accurate, because atomic weights are not integer values, but fractional ones.
So heavy!
But be careful - if you solve a problem intextbook on physics, you may encounter heavy forms of hydrogen, which have a different molar mass. The most common hydrogen is called protium and its mole weighs one gram, but there is also deuterium (2 g per mole) and tritium (3 g per mole). Deuterium in very small quantities (less than 0.2%) is found on Earth, and tritium almost never occurs at all, but it is easy to obtain in nuclear reactions. In the process of solving real problems, physics and chemistry are not distinguished, therefore, if you are preparing for a career in the natural sciences, you must be ready to determine the molar mass of hydrogen in such non-standard situations.
Calculations for the molecular form
If the problem is gas, then you needwill multiply the atomic mass of hydrogen by two and assign the unit g per mole. Atomic units and grams per mole are numerically equivalent, but the former are used more in physics and the discussion of the properties of elements, and the latter are used in solving practical problems in chemistry. But here you can catch and ask about the mass of heavy hydrogen. By the way, be careful, sometimes you will not be expected to multiply 2 or 3 in two. There are hybrid forms, for example, deuterium with tritium (the molar mass of hydrogen will be 2 + 3 = 5), or protium with deuterium (3), or tritium with protium (4). Therefore, reason logically and add, rather than multiply, so as not to be mistaken with heavy molecules.
The interesting thing is that the water that is heavyhydrogen is also called heavy. The tasks of obtaining it from heavy hydrogen can be difficult and it is for this purpose that you may have to calculate what the molar mass of hydrogen is in your particular situation.
