A,Fe=56g/mol
m=n(niu)x A
m= 12molx56g/mol= .................. calculeaza !!
A,Sc=45g/mol
n=m.A
n= 11,25g/45g/mol=0,25mol ioni
n=N/N,A-----> N= 0,25mol x 6,023x10²³ioni/mol=.................calculeaza !!!
M,K2O=(2x39gK+16gO)/mol= 94g/mol
1molK2O.(94g)...........2mol ioni K(+)
x..........................0,3mol
x= 0,3x94/2=.......................calculeaza masa K2O