Key Concepts and Definitions

Concentrations — Chemists and engineers seldom work with pure solutions of materials. In tact, more often than not we work with very minute amounts of materials dispersed in environmental media. A knowledge of units of concentration is required. Units of concentration in common usage for aqueous solutions include parts per million (ppm) and with increasing analytical capability and 

Fire and Explosion Hazards Handbook of Industrial Chemicals 

Solubility Product — The solubility product constant commonly referred to as the solubility product provides a convenient method of predicting the solubility of a material in water at equilibrium. Copper hydroxide, for example, dissolves according to the following equilibrium  

The resultant solubility product is represented in die following manner  

Note that the brackets, [ ], refer to the concentration of the species. Ksp is the solubility product constant hence [Cu2+] and [OH ]2 are equal to the molar concentrations of copper and hydroxyl ions, respectively. The Ksp is commonly used in determining suitable precipitation reactions for removal of ionic species from solution. In the same example, the pH for removal of copper to any specified concentration can be determined by substituting die molar concentration into the following equation  

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