Problem 136 - General Chemistry

Question

Silver nitrate reacts with strontium chloride in an aqueous precipitation reaction. What are the formulas of silver nitrate and strontium chloride? Write the molecular equation and net ionic equation for the reaction. What are the names of the products? Give the molecular equation for another reaction that produces the same precipitate.

Step-by-Step Solution

Answer

Silver nitrate is \( \text{AgNO}_3 \) and strontium chloride is \( \text{SrCl}_2 \). The molecular equation is \( 2\text{AgNO}_3(aq) + \text{SrCl}_2(aq) \rightarrow 2\text{AgCl}(s) + \text{Sr(NO}_3)_2(aq) \). The net ionic equation is \( 2\text{Ag}^+(aq) + 2\text{Cl}^-(aq) \rightarrow 2\text{AgCl}(s) \). Products: silver chloride and strontium nitrate. Alternate: \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{AgCl} + \text{NaNO}_3 \).

Step 1: Identify Reactants

Silver nitrate has the chemical formula \( \text{AgNO}_3 \), while strontium chloride has the formula \( \text{SrCl}_2 \). These are the compounds that will react in the given reaction.

Step 2: Write Molecular Equation

The molecular equation for the reaction between silver nitrate (\( \text{AgNO}_3 \)) and strontium chloride (\( \text{SrCl}_2 \)) can be written as:\[2\text{AgNO}_3(aq) + \text{SrCl}_2(aq) \rightarrow 2\text{AgCl}(s) + \text{Sr(NO}_3)_2(aq)\]In this reaction, silver chloride (\( \text{AgCl} \)) precipitates out of the solution.

Step 3: Write Net Ionic Equation

The net ionic equation focuses on the components that form the precipitate:\[2\text{Ag}^+(aq) + 2\text{Cl}^-(aq) \rightarrow 2\text{AgCl}(s)\]This highlights the formation of solid silver chloride from silver ions and chloride ions.

Step 4: Identify and Name the Products

The products of the reaction are strontium nitrate (\( \text{Sr(NO}_3)_2 \)) and silver chloride (\( \text{AgCl} \)). Silver chloride is the precipitate formed during the reaction.

Step 5: Alternative Reaction for Same Precipitate

Another reaction that produces the same precipitate, silver chloride (\( \text{AgCl} \)), is the reaction of silver nitrate (\( \text{AgNO}_3 \)) with sodium chloride (\( \text{NaCl} \)):\[\text{AgNO}_3(aq) + \text{NaCl}(aq) \rightarrow \text{AgCl}(s) + \text{NaNO}_3(aq)\]This reaction also results in the formation of silver chloride as a precipitate.

Key Concepts

Precipitation Reaction

A precipitation reaction occurs when two soluble salts are combined in solution, resulting in the formation of an insoluble solid, called a precipitate. In our case, the reaction involves silver nitrate and strontium chloride in solution.
The product, silver chloride, is the precipitate because it does not dissolve in water. Think of a precipitation reaction like a chemical surprise! You mix two solutions, and suddenly, a solid appears out of nowhere. Some key points about precipitation reactions include:

• The reactants are usually in aqueous solution.
• To identify a precipitate, you can refer to solubility rules or check solubility charts.

This type of reaction is fundamental in chemistry for understanding solubility and various separation techniques.

Molecular Equation

The molecular equation provides a complete overview of the chemical reaction, reflecting all reactants and products in their molecular form. It offers insight into the stoichiometry of the reaction, thereby showing the exact proportions of reactants needed to fully undergo the reaction.For the reaction between silver nitrate (\( \text{AgNO}_3 \)) and strontium chloride (\( \text{SrCl}_2 \)), the molecular equation is:\[2\text{AgNO}_3(aq) + \text{SrCl}_2(aq) \rightarrow 2\text{AgCl}(s) + \text{Sr(NO}_3)_2(aq)\]In this equation:

• Silver chloride (\( \text{AgCl} \)) is the product that precipitates out of the solution.
• Strontium nitrate (\( \text{Sr(NO}_3)_2 \)) remains dissolved.

This helps visualize the exchange and formation of different substances during the reaction.

Net Ionic Equation

The net ionic equation zeroes in on the ions that directly participate in forming the precipitate. It's like cutting out all the non-essential actors to understand the core process.For our reaction, the net ionic equation simplifies to:\[2\text{Ag}^+(aq) + 2\text{Cl}^-(aq) \rightarrow 2\text{AgCl}(s)\]Important aspects to note:

• Only the ions forming the solid are displayed, showing the actual species involved in the precipitation.
• Spectator ions, which do not participate in the actual formation of the precipitate, are omitted from this equation.

This highlights the primary chemical transformation occurring during the reaction.

Silver Nitrate

Silver nitrate, a versatile and widely used chemical compound, has the formula \(\text{AgNO}_3\). It is known for its complete solubility in water, making it a common reagent in precipitation reactions.Key characteristics of silver nitrate include:

• It acts as a source of silver ions (\(\text{Ag}^+\)).
• It is used in reactions to test for the presence of halide ions, such as chloride.

In the precipitation reaction with strontium chloride, silver nitrate provides the silver ions necessary to form solid silver chloride, a well-known white precipitate.

Strontium Chloride

Strontium chloride is represented by the formula \( \text{SrCl}_2 \). It is another soluble compound that plays a key role in forming precipitates via reaction with other soluble substances.In our specific reaction, strontium chloride:

• Contributes chloride ions (\(\text{Cl}^-\)) which are crucial for forming the silver chloride precipitate.
• Remains dissolved as strontium nitrate (\(\text{Sr(NO}_3)_2 \)) unlike the precipitate.

Understanding strontium chloride’s behavior in reactions helps predict when and how precipitates will form.