Question

va rog mult, urgent.

Answer 1

Mcristalohidrat = 160+90 = 250g/mol

250g cristalohidrat...........160g CuSO₄..........90g H₂O
3,125g................................xg.......................yg

x = 2g CuSO₄      ,  y = 1,125g H₂O

n = m/M = 2/160 = 0,0125 moli CuSO₄

a. C = n/Vs = 0,0125/0,1 = 0,125 moli/L

b. Vs = 10mL
C = 0,125 moli/L

C = n/Vs ⇒ n = C*Vs = 0,125*0,01 = 0,00125 moli CuSO₄

CuSO₄ + 2NaOH ⇒ Na₂SO₄ + Cu(OH)₂

n CuSO₄ = n Cu(OH)₂  = 0,00125 moli

Cu(OH)₂ + 4NH₃ ⇒ [Cu(NH₃)₄](OH)₂

M[Cu(NH₃)₄](OH)₂ = 166g/mol

1 mol Cu(OH)₂...........................166g [Cu(NH₃)₄](OH)₂
0,00125 moli..............................x = 0,2075g = 207,5mg reactiv..

1 mol Cu(OH)₂...............4 moli NH₃
0,00125 moli................x  = 0,005 moli NH₃

0,005 moli NH₃..............100%
x moli ............................150%

x = 0,0075 moli NH₃

C = n/Vs ⇒ Vs = n/C = 0,0075/0,15 = 0.05 L = 50 mL sol. NH₃

Nu stiu ce am gandit gresit de rezultatele nu coincid..