1) MAl(OH)3 = 78g/mol
n = m/M => m = n×M = 10×78 = 780g Al(OH)3
2) MH2CO3 = 62g/mol
%H = mH/MH2CO3×100 = 2/62×100 = 3,22
%C = 12/62×100 = 19,35
%O = 77,42
3) MCa(NO3)2 = 164g/mol
raport atomic => Ca:N:O = 1:2:6
raport masic => Ca:N:O = 40:28:96 = 10:7:24
4) nr atomi HNO3 = 3×5×6,022×10^23 = 9,033×10^24