a) 1. 2Ca+O2--->2CaO
2. CaO+H2O--->Ca(OH)2
3. Ca+2HNO3--->Ca(NO3)2+H2
4. CaO+N2O5--->Ca(NO3)2
5. Ca(OH)2+2HNO3--->Ca(NO3)2+2H2O
6. Ca+Cl2--->CaCl2
7. CaO+2HCl--->CaCl2+H2O
8. Ca(OH)2+2HCl--->CaCl2+2H2O
b) 1. 2Cu+O2--->2CuO
2. CuO+H2SO4--->CuSO4+H2O
3. CuO+2HCl--->CuCl2+H2O
4. CuSO4+2NaOH--->Cu(OH)2↓+Na2SO4
5. CuCl2+2KOH--->Cu(OH)2↓+2KCl
6. Cu(OH)2+H2SO4--->CuSO4+2H2O
7. Cu(OH)2+2HNO3--->Cu(NO3)2+2H2O