Acids generating nascent gas atoms
When concentrated sulfuric acid is heated, then it decomposes via the reaction 
$$\ce{H2SO4 -&gt; H2O + SO3}$$

I tried to determine under what circumstances the nascent oxygen (a free single atom of oxygen) is formed which would react with copper to create $\ce{CuO}$ but couldn't find the reaction in any modern source. I did find the proposed reaction in Essentials of Modern Chemistry
 By Charles Elwood Dull (1918) but I'm guessing that the reaction to give nascent oxygen is just wrong.   

The gist here is that you can't piece reactions together from balanced equations but you must also define the conditions under which the reaction takes place. At a deeper level not only can the chemical equation be specified but also the mechanism of the reaction can be detailed. 

Hydrochloric acid, $\ce{HCl}$, is typically in aqueous solution. Although copper won't react with pure hydrochloric acid, it can react with dissolved oxygen in hydrochloric acid.
$$\ce{Cu (s) + 2HCl (aq) + 1/2O2 (aq) -&gt; CuCl2 (aq) + H2O}$$

Oxygen can also be formed in chlorine water:
$$\begin{align}
  \ce{Cl2 (aq) &amp;-&gt; HCl + HOCl}\\
  \ce{HOCl &amp;-&gt; HCl + 1/2O2}
\end{align}$$

But the concept of nacent oxygen from this reaction is wrong.