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.
Wavelength = 434nm = 434 x 10⁻⁹m planck's constant = <span>h= 6.626 x 10 ⁻³⁴ J E =? by using the formula; E = hc /</span>λ value for c is 3 x 10⁸ m/s E = (6.626 x 10 ⁻³⁴ J)(3 x 10⁸ m/s) / 434 x 10⁻⁹m E = 1.9878 x 10⁻²⁵ / 434 x 10⁻⁹m E = 4.58 x 10⁻¹⁹ joules
