Question

400 g solutie NaOH de concentratie c1=10%reactioneaza cu o solutie de HCL de concentratie 50%
a) Ce cantitate de solutie de HCL s-a consumat .
b) ce produsi rezulta si cate grame din fiecare substanta

Answer 1

a)NaOH+HCl→NaCl+H₂O
c=md*100/ms → md=c*ms/100=10*400/100=40 g NaOH
n=m/M=40/40=1 mol NaOH
1 mol NaOH...........1 mol HCl
1 mol NaOH.........x                               x= 1 mol HCl
M HCl=1+35.5=36.5 g/mol
m HCl= 1*36.5=36.5 g HCl
c=md*100/ms →ms=md*100/c=36.5*100/50=71 g solutie HCl
b) In urma reactiei chimice dintre NaOH si HCl rezulta NaCl si H₂O ca produsi de reactie. 
1 mol NaOH...............1 mol NaCl...................1 mol H₂O
1 mol NaOH................x..................................y
x=1 mol NaCl 
M NaCl=23+35.5=58.5 g/mol
m NaCl=1*58.5=58.5 g NaCl
y=1 mol H₂O
MH₂O=2+16=18 g/mol
m H₂O=1*18=18 g H₂O