a) n=m/M=1.8/18=0.1 moli H2O
1mol H2O..............6.022*10^23 molecule
0.1 moli H2O........x=6.022*10^22 molecule
b) n=V/Vm=67.2/22.4=3 moli H2
1 mol H2........6.022*10^23 molecule
3moli H2............x=18.066*10^23 molecule
c) 1mol Al2O3.......6.022*10^23 molecule
x=0.83 moli..........................5 molecule
mAl2O3=0.83*102=84.66g Al2O3
d) 1 mol HCl...........6.022*10^23 molecule
x=0.3 moli...................1.8066*10^23 molecule
e) n=V/Vm=2.24/22.4=0.1 moli Cl2
1mol Cl2..........6.022*10^23 molecule
0.1 moli Cl2.....x=6.022*10^22 molecule