Mg(NO3)2
se cer masele de Mg,N,O care se gasesc in 100g sare !
M,=(24gMg + 2x14gN+6x16gO)/mol=148g/mol
148g sare........24gMg ...............28gN..........96gO
100g.............x..........................................y......................z
x= 2400/148=>17,1% Mg
y= 2800/148=.......................calculeaza
z= 9600/148=...............................calculeaza !!!!
pentru a calcula numarul de moli dintr-o masa data, se aplica formula
n(niu)= m/M
M,CH4=16g/mol
niu= 80g/16g/mol=5 mol
