Dissociation is the separation of ions that occurs when a solid ionic compound dissolves. It is important to be able to write dissociation equations. Simply undo the crisscross method that you learned when writing chemical formulas of ionic compounds. The subscripts for the ions in the chemical formulas become the coefficients of the respective ions on the product side of the equation. The formula unit of sodium chloride dissociates into one sodium ion and one chloride ion. The calcium nitrate formula unit dissociates into one calcium ion and two nitrate ions.
The ammonium phosphate formula unit dissociates into three ammonium ions and one phosphate ion. Note that the polyatomic ions themselves do not dissociate further, but remain intact.
Do not confuse the subscripts of the atoms within the polyatomic ion for the subscripts that result from the crisscrossing of the charges that make the original compound neutral.
The 3 subscript of the nitrate ion and the 4 subscript of the ammonium ion are part of the polyatomic ion and simply remain as part of its formula after the compound dissociates. Notice that the compounds are solids s which then become ions in aqueous solution aq. Figure 1. Calcium nitrate is a typical ionic compound. Alfred Tennyson Andrew Lang. Joan Thursday Louis Joseph Vance. Spiritualism and the New Psychology Millais Culpin.
The chemical process by which the action of a solvent or a change in physical condition, as in pressure or temperature, causes a molecule to split into simpler groups of atoms, single atoms, or ions. The separation of an electrolyte into ions of opposite charge. Separation of a group of related psychological activities into autonomously functioning units, as in the generation of multiple personalities. Published by Houghton Mifflin Company.
The separation of a substance into two or more simpler substances, or of a molecule into atoms or ions, by the action of heat or a chemical process. Dissociation is usually reversible. In addition to promoting the blending of dissimilar compounds, emulsifying agents are also responsible for keeping the mixture stable, i. View Full Term. By clicking sign up, you agree to receive emails from Corrosionpedia and agree to our Terms of Use and Privacy Policy.
Dissociation is the process by which chemical molecules or ionic compounds such as salts, or complexes break down into simpler constituents such as atoms, ions or radicals, usually in a reversible manner, as do CO 2 and H 2 O at high temperatures. Dissociation is the opposite of association and recombination. Dissociation accelerates the rate of corrosion and increased pitting in the anode area in concentration cell, for example corroding of metal pipes in water treatment.
The corrosion of iron in the presence of hydrogen sulfide and water is also dependent on the dissociation of the hydrogen-sulfide molecule. Dissociation in chemistry is a general process in which molecules separate or split into smaller particles. The dissociation constant Ka is the ratio of dissociated to undissociated compound. The increase in temperature also leads to a higher dissociation and a higher dissociation constant.
The dissociation degree is the fraction of original solute molecules that have dissociated. In the case of very strong acids and bases, the degree of dissociation is close to 1.
Less powerful acids and bases have a lesser degree of dissociation.
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