Cu (s) + 4 HNO3 (aq) → Cu(NO3)2 (aq) + 2 H2O (l) + 2 NO2 (l)
This is an oxidation-reduction (redox) reaction:
Cu0 - 2 e- → CuII (oxidation)
2 NV + 2 e- → 2 NIV (reduction)
Cu is a reducing agent, HNO3 is an oxidizing agent.
Reactants:
- Cu
- Names: Copper
, Copper (dusts and mists, as Cu) 
, Cu - Appearance: Solid in various forms. turns green on exposure to moist air ; Reddish, lustrous, malleable, odorless solid.
- Names: Copper
- HNO3 – Nitric acid
- Other names: Aqua fortis , Spirit of niter , Eau forte
- Appearance: Colorless, yellow or red fuming liquid ; Colourless-to-yellow liquid with pungent odour ; Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]
- Other names: Aqua fortis
Products:
- Cu(NO3)2 – Copper(II) nitrate
- Other names: Cupric nitrate , Nitrato de cobre (II) , Нитрат меди (II) (безводный)
- Appearance: Blue crystals | hygroscopic
- Other names: Cupric nitrate
- H2O – Water, oxidane
- Other names: Water (H2O) , Hydrogen hydroxide (HH or HOH) , Hydrogen oxide
- Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas
- Other names: Water (H2O)
- NO2 – Nitrogen dioxide
- Other names: Nitrogen(IV) oxide , Deutoxide of nitrogen , Nitrogen peroxide
- Appearance: Brown gas ; Reddish-brown gas or brown or yellow liquid with pungent odour ; Yellowish-brown liquid or reddish-brown gas (above 70°F) with a pungent, acrid odor. [Note: In solid form (below 15°F) it is found structurally as N2O4.]
- Other names: Nitrogen(IV) oxide