Question

cate grame de piatra vanata trebuie sa dizolvam in 2250g pentru a obtinr o solutie de supfat de cupru de 6.4%

Answer 1

piatra vanata: CuSO4 × 5H2O
c=6.4%

c=mCuSO4/mH2Ot × 100
mH2O=2250 g

Notam "a" g CuSO4 × 5H2O
M=64+32+64+5×18=160+90=250g/mol

250 g CuSO4 × 5H2O...160 g CuSO4...90gH2O
a g CuSO4 × 5H2O...x g CuSO4...y g H2O

x=16a/25 g CuSO4
y=9a/25 g H2O

c= (16a/25/ 2250+9a/25) ×100
6.4/100=16a/25/56250+9a/25
0.064=16a/25 × 25/56250+9a
0.064=16a/56250+9a
0.064 (56250+9a)=16a
3600+0.576a=16a
3600=16a-0.576a
3600=15.424a
a=3600/15.424
a=233.4 g CuSO4 × 5H2O