Copper reacts with nitric acid and sulfuric acid. It reacts with cold, dilute nitric acid, but it requires heat and concentrated sulfuric acid to create a reaction. Copper does not react with most other acids.
The reaction between copper and nitric acid is a popular classroom demonstration due to the visible production of nitrogen dioxide, but proper safety precautions must be taken. The nitrogen dioxide gas produced is toxic when inhaled, so the experiment should be performed under a fume hood or the nitrogen dioxide should be bubbled through water. Gloves and eye protection are important due to the corrosive nature of nitric acid.