Chemical reactions

Reaction of copper with acids

Copper metal dissolves in hot concentrated sulphuric acid forming Cu(II) ions and hydrogen, H2. In water, Cu(II) is present as the complex ion [Cu(H2O)6]2+ [8].

Cu(s) + 2 H2SO4(aq) Cu2+(aq) + SO42−(aq) + H2(g) + SO2(g) + 2 H2O(l)

Copper metal also dissolves in dilute or concentrated nitric acid, HNO3.

3 Cu(s) + 2 NO3(aq) + 8 H+(aq) 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l)

Reaction of copper with air

Copper metal is stable in air under normal conditions. When heated until red hot, copper metal and oxygen react to form Cu2O.

4 Cu(s) + O2(g) 2 Cu2O(s)

Reaction of copper with ammonia

Copper(II)ions are precipitated by ammonia:

[Cu(H2O)6]2+(aq) [blue] + 2 NH3(aq) [Cu(OH)2(H2O)4](s) [blue] + 2 NH4+(aq)

The precipitate dissolves in excess amonia.

[Cu(OH)2(H2O)4](s) + 4 NH3(aq) [Cu(NH3)4]2+(aq) [royal blue] + 2 H2O(l) + 2 OH(aq)

Reaction of copper with carbonate

Cu(II) is precipitated by carbonate:

[Cu(H2O)6]2+(aq) [blue] + CO32−(aq) CuCO3(s) [blue] + 6 H2O(l)

Reaction of copper with halogens

Metallic copper metal reacts with the halogens forming corresponding dihalides.

Cu(s) + F2(g) CuF2(s) [white]
Cu(s) + Cl2(g) CuCl2(s) [yellow-brown] [8]
Cu(s) + Br2(g) CuBr2(s) [black] [8]

Cu(II) forms yellow complexes with 4 Cl. The complex looks green to bluish green, due to the mixture with the blue aqua complex [8]:

[Cu(H2O)6]2+(aq) [blue, octahedral] + 4 Cl(aq) [CuCl4]2−(aq) [yellow, tetrahedral] + 6 H2O(l)

Cu(II) is precipitated by Br, forming a black solid [8]:

Cu2+(aq) + 2 Br(aq) CuBr2(s)

Cu(II) is reduced to Cu(I) and precipitated by I [8]:

2[Cu(H2O)6]2+(aq) [blue, octahedral]) + 4 I(aq) 2 CuI(s) [white] + I2(aq) + 6 H2O(l)

Reaction of copper with hydroxide

Cu(II) is precipitated by hydroxide. Concentrated hydroxide will dissolve the precipitate:

[Cu(H2O)6]2+(aq) [blue] + 2 OH(aq) Cu(OH)2(H2O)4(s) [light blue] + 2 H2O(l)
2 Cu(OH)2(s) [light blue] + 3 OH(aq) [Cu(OH)4]2−(aq) [blue] + [Cu(OH)3](aq) [blue]

Reaction of copper with metal/metal ions

Copper is oxidized by Hg(II)

Hg2+(aq) + Cu(s) Hg(l) + Cu2+(aq)

Copper(II) is reduced by iron and zinc

3 Cu2+(aq) + 2 Fe(s) 3 Cu(s) + 2 Fe3+(aq)
Cu2+(aq) + Zn(s) 3 Cu(s) + Zn2+(aq)

Reaction of copper with sulfide

Copper(II) is precipitated by sulfide in 0.4 M hydrochloric acid

Cu2+(aq) + H2S(aq) CuS(s) + 2 H+(aq)

Reaction of copper with water

Copper(II) forms a hexaqua complex with water. The complex is slightly acidic, due to hydrolysis [8]

[Cu(H2O)6]2+(aq) + H2O(l) [Cu(H2O)5(OH)]+(aq) + H3O+(aq)

Quantitative analysis

Method 3500-Cu C Inductively Coupled Plasma Method [1]. A portion of the sample is digested in a combination of acids. The digest is aspirated into an 8,000 K argon plasma where resulting light emission is quantified for 30 elements simultaneously.

Method limit of detection in water = 0.002 mg/L
Method limit of detection in soil = 1.00 mg/kg