Question

Care este concentratia procentuala a 400g solutie H2SO4 daca reactioneaza cu 500g sol NaOH de concetratie C=20%?

MULTE PUNCTEEEE

Answer 1

H2SO4 + 2NaOH = Na2SO4 + 2H2O;
m.sub(NaOH)=m.sol × ω ÷100% = 500g × 20% ÷100%= 100g;
υ(NaOH)= m÷M = 100g ÷ 40g/mol = 2,5mol;
υ(H2SO4)= 0,5 × 2,5mol =1,25 mol; m.sub(H2SO4)=υ × M =1,25 mol × 98 g/mol = 122,5 g
ω(H2SO4)=m.sub×100%÷m.sol =122,5g × 100% ÷ 400g = 30,625%

Answer 2

H2SO4 + 2NaOH = Na2SO4 + 2H2O

Aplicam concentratia pt. NaOH si rezulta:

c=mdizolvat*100/m solutie => m dizolvat= c*m solutie/100=20*500/100=100 g.

Calculam masa molecular pt. NaOH: 23+16+1=40

Calculam masa molecular pt. H2SO4: 2+32+4*16=98

Calculam cu o regula de 3 simpla cantitatea practica de H2SO4 de pe reactive :

   100g                   x g

2NaOH        +     H2SO4 ----->

  2*40                      98

 

x=100*98/2*40*98=122,5 g

Aplicam acum formula concentratie pt H2SO4: c=mdizolvat*100/m solutie= 122,5*100/400=30,625%