Răspuns:
se da m,=160gNaOH
se cunoaste miuNaOH= 40g/mol
miu Mg(OH)2=58g/mol
-calculez nr.moli NaOH
niu=m/miu= 160/40mol= 4mol NaOH
-deduc moli Mg(OH)2 din ecuatia chimica
2mol..............................1mol
2NaOH + MgCl2----> Mg(OH)2 + 2NaCl
4mol................................x
x=niu= 2mol Mg(OH)2
-calculez masa de Mg(OH)2
m= niuxmiu= 2x58g=116g
Explicație: