Question

Calculati-mi si mie: 
1320g Mg(PO₄)₂
gO=?

0,1 moli Fe₂O₃
gFe=?

3400g AgNO₃
moli N = ?          

Va rogggg!

Answer 1

Mg3(PO4)2 este formula corecta din cate stiu eu...grupa fosfat are valenta 3
masa molara fosfat = 3*24+2*(31+4*16)=262 g/mol
in 262 g fosfat.........8 * 16 g O
in 1320 g fosfat.......x g O             x = 644,8855 g O

Fe2O3 are masa molara = 2*56+3*16=160 g/mol
in 160 g oxid........2 * 56 g Fe
in 0,1 moli oxid=16 g oxid.........y g Fe          y = 11,2 g Fe

AgNO3 are masa molara = 108+14+3*16 = 170 g/mol
in 170 g azotat.......14 g azot
in 3400 g azotat..........z g azot             z = 280 g azot
nr moli = masa/masa molara azot
=> nr moli = 280/14 = 20 moli N simplu sau 280/28 = 10 moli N2 molecular...depinde