MO2 = 32g/mol
n=m/M=>m=n*M= 20*32 = 640g O2
MNa = 23g/mol
n=m/M=230/23=10 moli Na
MAl = 27g/mol
n=m/M = 54/27 = 2 moli Al
MS = 32g/mol
m S = 6*32 = 192g
nr atomi H2 = 2*2*NA = 4*NA = 4*6,022*10^23 atomi = 24,088*10^23 atomi H2
MS = 32g/mol
n=m/M=16/32=0,5 moli S
MK =39g/mol
m K = 4*39=156g