Equal amounts of whether the substance contains 4 g of hydrogen

given:
m(Н2) = 4 g
m(О2) = 64 g
find:
(Н2) - ?
(О2) - ?
Solution:
1- way:
М(Н2) = 2 g/mol
4 g Н2 ----- nbsp;х mol Н2
2 g Н2 ----- 1 mol Н2
х= (4 g nbsp; 1 mol)/(2 g) nbsp;nbsp;=2 mol
2- way:
М(Н2) = 2 g/mol
=m/М nbsp;;(Н) =(m(Н))/(М(Н)) nbsp;= (4 g)/(2g/mol) nbsp;= 2 mol.
1- way:
М(О2) = 32 g/mol
64 g О2 ----- nbsp;х mol О2
32 g О2 ----- 1 mol О2
х= (64 g nbsp; 1 mol)/(32 g) nbsp;nbsp;=2 mol
2- way:
М(О2) = 32 g/mol
=m/М nbsp;;(О) =(m(О))/(М(О)) nbsp;= (64 g)/(32 g/mol) nbsp;= 2 mol.
Answer: (Н2) = nbsp;2 mol; (О2) = nbsp;2 mol - Identical.