Răspuns :
M CH4=Ac+4Ah=12+4=16g/mol
16 g CH4........12gC
100....................p1
p1=12×100/16 => p1=75% C
16 g CH4........12gC
100....................p1
p1=12×100/16 => p1=75% C
16CH4...... 12g C 100.....p1 p1= 12x100/16 =>p1=75%C x=ori %=proccent/..............