Formation of Copper Sulfate Solution: Dissolving Copper Sulfate in Water or Copper in Concentrated Sulfuric Acid

Copper sulfate solution, commonly referred to as CuSO4 aq, forms in both scenarios where either copper sulfate dissolves in water or copper reacts with concentrated sulfuric acid. This article explores the chemical reactions involved in each process and highlights the key concepts related to solution formation.

Dissolving Copper Sulfate in Water

The first scenario involves dissolving copper(II) sulfate (CuSO4) in water (H2O). In this case, solid copper sulfate dissociates into an aqueous solution:

[ text{CuSO}_4 , text{s} rightarrow text{CuSO}_4 , text{aq}]

Copper Dissolving into Sulfuric Acid

The second scenario involves copper (Cu) reacting with a concentrated aqueous solution of sulfuric acid (H2SO4) to form copper(II) sulfate (CuSO4):

[ text{Cu} , text{s} text{H}_2text{SO}_4 , text{aq} rightarrow text{CuSO}_4 , text{aq} text{H}_2 , text{g}]

Both reactions result in the formation of copper sulfate in aqueous form. The first reaction is a simple dissolution process, while the second involves a more complex chemical reaction releasing hydrogen gas (H2).

Exothermic Reactions and Energy Change

The dissolution of anhydrous copper sulfate (CuSO4) in water or the reaction of copper with concentrated sulfuric acid can be discussed in terms of energy changes. Both processes are fundamentally exothermic and spontaneous, as indicated by negative changes in free energy (ΔG) and enthalpy (ΔH).

Anhydrous Copper Sulfate in Water

When anhydrous copper sulfate (CuSO4) is added to water:

[ text{CuSO}_4 , text{s} 5text{H}_2text{O} rightarrow text{CuSO}_4 cdot 5text{H}_2text{O}]

The change in free energy (ΔG20C) is -32.7 kJ, and the change in enthalpy (ΔH20C) is -78.0 kJ. Both values are negative, indicating that the reaction is spontaneous and exothermic.

Copper Reacting with Concentrated Sulfuric Acid

The reaction of solid copper with liquid sulfuric acid and water forms copper sulfate and hydrogen gas:

[ text{Cu} , text{s} text{H}_2text{SO}_4 , text{l} 5text{H}_2text{O} rightarrow text{CuSO}_4 cdot 5text{H}_2text{O} text{H}_2 , text{g} uparrow]

The change in free energy (ΔG20C) is -4.8 kJ, and the change in enthalpy (ΔH20C) is -35.2 kJ. Again, both values are negative, confirming that the reaction is exothermic and spontaneous.

Conclusion

Both processes result in the formation of copper sulfate in aqueous solution. Whether through the simple dissolution of copper sulfate or the oxidation of copper in concentrated sulfuric acid, the resulting product is copper(II) sulfate (CuSO4).

References

Further reading and detailed literature can be found in chemistry textbooks and scientific papers on the thermodynamics and reactions of copper sulfate and copper in sulfuric acid.