Check all of the reasons that you included in your answer.Copper oxide is the only product, and it contains copper and oxygen.One of the reactants is copper, so the other reactant must be oxygen.The copper metal must have combined with something in the air.
Answer
A
Copper oxide is the only product, and it contains copper and oxygen.
B
One of the reactants is copper, so the other reactant must be oxygen.
C
The copper metal must have combined with something in the air.
Explanation
Copper oxide contains copper and oxygen, so oxygen must have joined the copper to make the product. Since copper was already one reactant, oxygen was the other reactant. The oxygen could have come from the air, meaning the copper combined with something in the air.
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