Una muestra de 1 gramo de un elemento contiene 1,5 x 1022 atomos, cual es su masa molar❓❓

El número de Avogadro es 6,022 x 10^23, y es el número de átomos que hay en un mol de dicho elemento. A su vez un mol es la cantidad de un elemento cuya masa en gramos coincide con el peso atómico.

Por tanto, 6,022 x 10^23 átomos del elemento tienen una masa en gramos igual a su peso atómico. Hacemos una regla de tres:

1 gramo 1,5 x 10^22 átomos

x 6,022 x 10^23 átomos

=> x = 40,1 gramos por mol del elemento.

De modo que su peso atómico es 40,1. Se trata del calcio.

Saludos.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.