4. Cu(0)+H2(+1)S(+6)O4(-2)=Cu(+2)S(+6)O4(-2)+S(+4)O2(-2)+H2(+1)O(-2)
Cu(0)-2e= Cu(+2)
S(+6)+2e= S(+4)
Cu+2H2SO4=CuSO4+SO2+2H2O
CaO+2HCl=CaCl2+H2O
Mr CaO=56
Mr CaCl2=111
Mr H2O=18
n(CaO)=560/56=10 моль
n(CaO)=n(CaCl2)=n(H2O)
m CaCl2=10 × 111= 1110 gram
m H2O= 10×18= 180 gram
2NaOH+CO2=Na2CO3+H2O
6NaOH + P2O5=2Na3PO4
3NaOH+H3PO4=Na3PO4+3H2O
2NaOH+CuCl2=Cu(OH)2+2NaCl