Make up the reaction equation: Ba- BaO- Ba (OH) 2- BA (NO3) 2- BaCl2- BaSO4

1) 2Ba + O2 = 2BaO (when barium interacts with oxygen, barium oxide is formed);

2) BaO + H2O = Ba (OH) 2 (when barium oxide interacts with water, barium hydroxide is formed);

3) Ba (OH) 2 + 2HNO3 = Ba (NO3) 2 + 2H2O (when barium hydroxide interacts with nitric acid, barium nitrate and water are formed);

4) Ba (NO3) 2 + 2HCl = 2HNO3 + BaСl2 (when barium nitrate interacts with hydrochloric acid, nitric acid and barium chloride are formed);

5) BaCl2 + CuSO4 = BaSO4 + CuCl2 (when barium chloride interacts with copper sulfate, barium sulfate and copper chloride are formed).