Question

Determine whether each compound is soluble or insoluble. If the compound is soluble, list the ions present in solution. \(\begin{array}{ll}{\text { a. } \operatorname{AgNO}_{3}} & {\text { b. } \mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}} \\\ {\text { c. } \mathrm{KNO}_{3}} & {\text { d. }\left(\mathrm{NH}_{4}\right)_{2} \mathrm{S}}\end{array}\)

Short answer

All the compounds, AgNO3, Pb(C2H3O2)2, KNO3, and (NH4)2S are soluble. AgNO3 forms Ag+ and NO3- ions; Pb(C2H3O2)2 forms Pb2+ and C2H3O2- ions; KNO3 forms K+ and NO3- ions; (NH4)2S forms NH4+ and S2- ions in solution.

Step-by-step solution

Determine the solubility of AgNO3

Silver nitrate (AgNO3) is a compound that is typically soluble in water because all nitrates (NO3-) are soluble according to the solubility rules.

List the ions present in solution for AgNO3

Since AgNO3 is soluble, it dissociates in water to form ions. The ions present in the solution will be Ag+ and NO3-.

Determine the solubility of Pb(C2H3O2)2

Lead acetate, Pb(C2H3O2)2, is commonly soluble in water because acetates (C2H3O2-) are generally soluble according to the solubility rules.

List the ions present in solution for Pb(C2H3O2)2

Since Pb(C2H3O2)2 is soluble, it dissociates in water to form ions. The ions present in the solution will be Pb2+ and C2H3O2-.

Determine the solubility of KNO3

Potassium nitrate (KNO3) is soluble in water because all compounds containing potassium (K+) and all nitrates (NO3-) are soluble.

List the ions present in solution for KNO3

Being soluble, KNO3 dissociates in water to form K+ and NO3- ions.

Determine the solubility of (NH4)2S

Ammonium sulfide ((NH4)2S) is soluble in water because ammonium (NH4+) compounds are soluble.

List the ions present in solution for (NH4)2S

Since (NH4)2S is soluble, it dissociates to form NH4+ and S2- ions.

Key concepts

Dissociation of Ionic Compounds

When ionic compounds dissolve in water, they undergo a process called \textbf{dissociation}. This is where the solid crystal lattice of the compound breaks down into its constituent ions as it interacts with water molecules. For instance, when \textbf{silver nitrate (\(AgNO_3\))} is placed in water, it dissociates into silver ions (\(Ag^+\)) and nitrate ions (\(NO_3^-\)).

The extent to which an ionic compound will dissociate depends on the strength of the ionic bonds and the compound's solubility. Highly soluble compounds, such as \textbf{potassium nitrate (\(KNO_3\))}, dissociate almost completely, producing potassium (\(K^+\)) and nitrate (\(NO_3^-\)) ions in solution. Understanding dissociation is essential for predicting the behavior of ionic compounds in solutions, including how they conduct electricity and interact with other substances.

Soluble and Insoluble Compounds

The solubility of a compound is determined by its ability to dissolve in a solvent, such as water. Chemistry students must learn the \textbf{solubility rules} which provide guidelines on whether certain ionic compounds will dissolve, forming a homogeneous solution. Compounds like \textbf{lead acetate (\(Pb(C_2H_3O_2)_2\))}, due to the presence of acetate (\(C_2H_3O_2^-\)), are typically soluble in water.

On the other hand, some compounds are classified as insoluble if they do not appreciably dissolve in water. For instance, certain carbonates or phosphates usually stay intact as solids when mixed with water. Factors affecting solubility include temperature and the presence of other ions in the solution. In the classroom, students will often use solubility rules to predict whether a precipitation reaction will occur when different solutions are mixed.

Predicting Ion Formation in Solutions

The ability to predict which ions will be present in a solution is a crucial skill for students studying chemistry. According to the solubility rules, substances like \textbf{ammonium sulfide (\((NH_4)_2S\))} are soluble, hence we can predict the formation of \textbf{ammonium ions (\(NH_4^+\))} and \textbf{sulfide ions (\(S^{2-}\))} in solution.

Predicting ion formation allows one to anticipate possible chemical reactions, such as the formation of a precipitate or the outcomes of neutralization reactions. Knowledge of ionic equilibria is also involved, such as understanding the common ion effect and its influence on solubility. By mastering these predictions, students can apply this knowledge to various practical situations in laboratory experiments and real-world applications, reinforcing their comprehension of ionic compounds and their behaviors in solutions.