What proportion of moles is 1 g of hydrogen H2?

given:
m(Н2) = 1 g
find:
ν(Н2) - ?
Solution:
1- way:
М(Н2) =2 g/mol
1 g Н2  х mol Н2
2 g Н2 1 mol Н2
х= (1 g  • 1 mol)/2g   =1 mol
2- way:
М(Н2) = 2 g/mol
ν=m/М  ;ν(Н₂) =(m(Н₂))/(М(Н₂))  = (1 g)/(2 g/mol)  = 0,5 mol.
Answer: ν(Н2) =  0,5 mol.