Question

For the following chemical reactions, determine the precipitate produced when the two reactants listed below are mixed together. Indicate "none" if no precipitate will form.

Short answer

When silver nitrate (AgNO3) and sodium chloride (NaCl) are mixed together, a precipitate of silver chloride (AgCl) will form.

Step-by-step solution

Identify the given reactants

Firstly, we need to identify the given reactants. They will be provided by the person performing the experiment or in a given question. For this example, let's use the following reactants: 1. Silver nitrate (AgNO3) 2. Sodium chloride (NaCl) We will determine if a precipitate forms when these two reactants are mixed together.

Write the molecular equation

Write down the molecular equation of the reaction between the two given reactants. For our example, the molecular equation will look like this: AgNO3(aq) + NaCl(aq) → ?

Identify the possible products

Identify the possible products of the reaction by crossing the cations and anions of the reactants. The two possible products for our example are: 1. Silver chloride (AgCl) 2. Sodium nitrate (NaNO3) So the molecular equation now becomes: AgNO3(aq) + NaCl(aq) → AgCl(?) + NaNO3(?)

Apply solubility rules

Next, use solubility rules to determine if any of the possible products will form a precipitate. According to solubility rules: 1. All nitrates (NO3-) are soluble. 2. Most chlorides (Cl-) are soluble, except for silver chloride (AgCl), lead chloride (PbCl2), and mercury(I) chloride (Hg2Cl2), which are insoluble. With this information, we can conclude that silver chloride (AgCl) will form a precipitate, while sodium nitrate (NaNO3) will remain aqueous. Therefore, the molecular equation now becomes: AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)

Write the net ionic equation

Now, write the net ionic equation by excluding the spectator ions. In this case, the spectator ion is the nitrate (NO3-) ion. The net ionic equation is: Ag+(aq) + Cl-(aq) → AgCl(s)

Interpret the result

Based on the net ionic equation, we can conclude that when silver nitrate (AgNO3) and sodium chloride (NaCl) are mixed together, a precipitate of silver chloride (AgCl) will form.

Key concepts

Solubility Rules

Understanding solubility rules is crucial in predicting the outcome of chemical reactions, particularly when dealing with aqueous solutions. A key principle is that not all ionic compounds dissolve in water. Solubility rules are guidelines that help us predict which ionic compounds are soluble and which ones are not.

When two solutions are mixed, they may form a new compound that could be insoluble, leading to the formation of a precipitate. For instance, while most chloride (Cl^-) salts are soluble in water, there are notable exceptions such as silver chloride (AgCl), lead(II) chloride (PbCl₂), and mercury(I) chloride (Hg₂Cl₂). Similarly, although nitrates (NO₃^-) are generally soluble, applying these rules allows us to predict that AgNO₃ and NaCl will react to form insoluble AgCl, which precipitates out of the solution.

Molecular Equations

Molecular equations provide a view of the reactants and products in their complete, non-dissociated forms. They are an integral part of understanding chemical reactions. For instance, when we mix silver nitrate (AgNO₃) and sodium chloride (NaCl), the molecular equation would look like:

AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq).

This equation tells us that reactants are in aqueous solution, indicated by (aq), and the silver chloride (AgCl) forms as a solid precipitate, indicated by (s). The sodium nitrate (NaNO₃) remains in solution. The molecular equation provides a clear picture of the chemical process before dissociation into ions.

Net Ionic Equations

Moving beyond the overall reaction, net ionic equations focus on the ions that actually participate in the chemical change. These equations remove the spectator ions, which do not partake in the formation of the precipitate.

Using the previous example, the net ionic equation for the precipitation of silver chloride from silver nitrate and sodium chloride is:

Ag⁺(aq) + Cl^-(aq) → AgCl(s).

The nitrate (NO₃^-) and sodium (Na⁺) ions remain in the solution and do not participate in forming the precipitate; thus, they are excluded from the net ionic equation. This simplification helps us focus on the essence of the reaction—the formation of the insoluble compound.

Reactants and Products in Chemistry

In every chemical reaction, the starting materials are called reactants, and the substances formed are known as products. Reactants undergo chemical changes to become products through the process of a chemical reaction.

In our textbook example, the reactants are silver nitrate (AgNO₃) and sodium chloride (NaCl), and the products are silver chloride (AgCl), the precipitate, and sodium nitrate (NaNO₃), which remains dissolved. The transformation from reactants to products involves breaking old bonds and forming new ones, which can be precipitated by changes in conditions such as temperature, concentration, or by mixing different compounds as demonstrated in the chemical equation.