Question

Write a chemical equation that represents \(\mathrm{SrCl}_{2}(\mathrm{~s})\) dissociating in water.

Short answer

\(\mathrm{SrCl}_{2}( ext{s}) \rightarrow \mathrm{Sr}^{2+}( ext{aq}) + 2 \mathrm{Cl}^{-}( ext{aq})\)

Step-by-step solution

Understand Dissociation

Dissociation in a chemical context refers to the process where a compound breaks down into its ions when dissolved in water. For ionic substances like \(SrCl_2\), this means splitting into its constituent ions.

Identify the Ions

The compound \(SrCl_2\) is composed of one strontium ion \(Sr^{2+}\) and two chloride ions \(Cl^-\). When \(SrCl_2\) dissolves in water, it dissociates into these ions.

Write the Chemical Equation

To express the dissociation of \(SrCl_2\) in water, we write:\[\mathrm{SrCl}_{2}( ext{s}) \rightarrow \mathrm{Sr}^{2+}( ext{aq}) + 2 \mathrm{Cl}^{-}( ext{aq})\]This equation shows that solid \(SrCl_2\) dissociates into one aqueous \(Sr^{2+}\) ion and two aqueous \(Cl^-\) ions.

Key concepts

Chemical Equations

A chemical equation is like a recipe for a chemical reaction, showing how the reactants (the starting materials) change into the products (the end results). It's a concise way to express what happens in a chemical reaction using symbols and formulas. For instance, when strontium chloride (\(\text{SrCl}_2\)) dissociates in water, it breaks into ions. We can represent this change with a chemical equation:\[\mathrm{SrCl}_{2}(\mathrm{s}) \rightarrow \mathrm{Sr}^{2+}(\mathrm{aq}) + 2 \mathrm{Cl}^{-}(\mathrm{aq})\]This is saying that solid \(\text{SrCl}_2\) when placed in water, separates into one strontium ion \(\text{Sr}^{2+}\) and two chloride ions \(\text{Cl}^-\). Writing chemical equations is crucial in chemistry because:

• They show what substances are involved in the reaction.
• They indicate the states of those substances, such as solid (\(\text{s}\)), liquid (\(\text{l}\)), gas (\(\text{g}\)), or aqueous (\(\text{aq}\)) - the latter meaning dissolved in water.
• They illustrate how matter and charge are conserved throughout the reaction.

Strontium Chloride

Strontium chloride is a chemical compound with the formula \(\text{SrCl}_2\). It's made of strontium and chlorine and is typically found as a solid at room temperature. This compound readily dissolves in water, undergoing a process known as dissociation.In \(\text{SrCl}_2\), there are key elements:

• Strontium Ion (\(\text{Sr}^{2+}\)): This is a positively charged ion. In the periodic table, strontium belongs to the alkaline earth metals, known for forming \(\text{2+}\) cations.
• Chloride Ions (\(\text{Cl}^-\)): These are negatively charged ions. Chlorine is a halogen, which typically gains one electron to form an ion with a \(\text{1-}\) charge.

When \(\text{SrCl}_2\) dissolves in water, these ions separate, which is useful in various applications including road de-icing and even in some toothpaste formulations. Understanding how \(\text{SrCl}_2\) behaves when it dissolves helps us predict its properties and reactions in aqueous environments.

Aqueous Solutions

An aqueous solution is a solution where water is the solvent. When substances like strontium chloride dissolve in water, they form aqueous solutions. In aqueous solutions, ionic compounds separate into their respective ions. Water, being a polar molecule, has a unique ability to dissolve many substances, especially ionic compounds. This is because:

• Water molecules surround and interact with the ions of the compound, effectively reducing the electrostatic forces holding them together.
• The positive pole of water (the hydrogen) is attracted to negative ions, while the negative pole (the oxygen) is attracted to positive ions.

This interaction allows compounds like \(\text{SrCl}_2\) to dissociate into strontium ions (\(\text{Sr}^{2+}\)) and chloride ions (\(\text{Cl}^-\)), which are now free to move in the solution. The ability to conduct electricity is one of the indicators of an aqueous solution's ionic nature because the free ions act as charge carriers. Understanding the nature of aqueous solutions is fundamental in chemistry as they are vital in various chemical processes and reactions.