Mole - one of the most important concepts in chemistry - is a kind of link to go from the microworld of atoms and molecules in a normal macrocosm grams and kilograms.
In chemistry often have to consider large numbers of atoms and molecules. For fast and efficient calculation made using the weighing method. But it is necessary to know the weight of individual atoms and molecules. In order to identify the molecular weight must be added the weight of all atoms in the compound.
A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe.
C) a chemical change.
Chemical reactions will always convert a certain chemical(s) into one or more products.
