Boil 100 mL of water with 50 g of cane sugar (sucrose) and add 1 g of citric acid, boil until the mixture is very thick, this hydrolyzes the sucrose into glucose and fructose, max glucose yield is 80%. Mix 200 mL water, 30 g copper sulfate, 17 g citric acid and 30 g sodium bicarbonate (Sodium hydroxide can be also used as the equation says, but the sodium hydroxide can react with the oxide) with heating to form copper citrate complex compounds. Mix both liquids and boil them until you have brick red precipitate which is copper (I) oxide and the remaining solution is clear or brownish. If the reaction doesn’t start to get color add more of the sodium bicarbonate.
2CuSO4 + 4NaOH+ C6H12O6 = Cu2O + 2Na2SO4 + C6H12O7 + 2H2O
The copper citrate complex in base medium
Copper (I) oxide is precipitating
The bubbling stopped and all of the copper (I) oxide has precipitated.
Copper (I) oxide
Copper (I) oxide drying