S.93 10-5

n=\frac{m}{M}
 
n= Aine määrä (mol)
m= Massa (g)
M= Moolimassa (g/mol)
 
m\left(H_2\right)=12g
M\left(H_2\right)=1{,}008\frac{g}{mol}\cdot2=2{,}016\frac{g}{mol}
n=\frac{m}{M}=\frac{12g}{2{,}016\frac{g}{mol}}=5{,}9523...\approx6{,}0mol
 
n=\frac{N}{N_A}\ <=>\ N=nN_A
N\left(H_2\right)=5{,}952mol\cdot6{,}022\cdot10^{23}=3{,}584\cdot10^{24}\approx3{,}6\cdot10^{24}