Question

Afla numarul de molecule de clor care in reactie cu H2 sa formeze 73 mg HCl

Answer 1

Transformi 70mg in g: 0.073g HCl
MCl2=71g/mol
MHCl=36.5g/mol
Lucrezi pe reactie, pui masele molare jos si masele sus:

  x.............0.073g
Cl2+H2->2HCl
 71...........2*36.5

Regula de 3 simpla: x=(71*0.073)/(2*36.5); x=0.071g Cl
regula de 3 simpla din nou: un mol de clor molecular are 71g, 0.071g Cl o sa fie y moli
1mol.....71g
y............0.071g
y=0.071/71
y=0.001 moli Cl

Un mol de orice substanta contine 6.023*10^23 unitati (molecule/atomi/etc.), deci 0.001moli Cl o sa aiba 0.00602*10^23 molecule.
Sper sa nu fi gresit.