Question

cho 400gam dung dịch H2SO4 tác dụng hết với 13 gam Zn. Tính:

a) C% dd axit đã dùng

b) C% dd muối sinh ra

Answer 1

n_H2SO4=\(\dfrac{400}{98}=4,08\left(mol\right)\)

n_Zn=\(\dfrac{m}{M}=\dfrac{13}{65}=0,2\left(mol\right)\)

pthh:

H₂SO₄ + Zn \(\rightarrow\) ZnSO₄ + H₂\(\Rightarrow\) H₂SO₄ dư

0,2.........0,2..... ..0,2..... ...0,2(mol)

a, C%_{dd h2so4}=\(\dfrac{m_{ct}}{m_{dd}}.100\%=\dfrac{n.M}{400}.100\%=\dfrac{0,2.98}{400}.100\%=4,9\%\)

b, m_{dd ZnSO4}=400+13-m_H2=413-0,4=412,6(g)

C%_{dd ZnSO4}=\(\dfrac{n.M}{412,6}.100\%=\dfrac{0,2.161}{400}.100\%=8,05\%\)