CuS is a reducing agent, HNO3 is an oxidizing agent.
[external_link offset=2]
Reactants:
CuS – Copper sulfide
Other names: Copper monosulfide, Covellite, Copper(II) sulfide, Cupric sulfide
Appearance: Black powder or lumps
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.]
Products:
Cu(NO3)2 – Copper(II) nitrate
Other names: Cupric nitrate, Nitrato de cobre (II), Нитрат меди (II) (безводный)
Appearance: Blue crystals | hygroscopic
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.]
S
Names: Sulfur, S, Sulphur
Appearance: Yellow solid in various forms
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