Write a balanced chemical reaction for the dissolution of your copper oxide sample in hydrochloric acid

Copper oxide reacts with hydrochloric acid to produce copper chloride and water.

So the basic equation that illustrates this reaction is:
CuO + HCl > CuCl2 + H2O

Now, we need to balance this equation:
the number of copper and oxygen moles are balanced.
For each of hydrogen and chlorine, we have one mole as a reactant and two moles as product.
Therefore, to balance this, we will add an extra mole of HCl in the reactants.

Based on this, the final balanced equation would be:
CuO + 2HCl > CuCl2 + H2O

They carry out the exchange of gases as we breathe ( oxygen and carbon dioxide).