Question

Describe, by both formal and ionic equations, what takes place when \(0.10\) mole of sodium sulfite is added to 1 liter of \(1 \mathrm{M}\) hydrochloric acid.

Short answer

In summary, when 0.10 moles of sodium sulfite reacts with 1 liter of 1M hydrochloric acid, the balanced chemical equation is: \(Na_2SO_3 + 2HCl \to 2NaCl + H_2O + SO_2\). The complete ionic equation is: \(2Na^+ + SO_3^{2-} + 2H^+ + 2Cl^- \to 2Na^+ + 2Cl^- + H_2O + SO_2\), and the net ionic equation is: \(SO_3^{2-} + 2H^+ \to H_2O + SO_2\).

Step-by-step solution

Write the balanced chemical equation for the reaction

Sodium sulfite (Na2SO3) reacts with hydrochloric acid (HCl) as follows: \[Na_2SO_3 + 2HCl \to 2NaCl + H_2O + SO_2\]

Determine the moles of each reactant

We are given that 0.10 moles of sodium sulfite is added to 1 L of 1 M hydrochloric acid. Moles of sodium sulfite: 0.10 moles Moles of hydrochloric acid: 1 L * 1 mol/L = 1 mol

Write down the complete ionic equation

First, break down each soluble ionic compound into its respective ions: \[2Na^+ + SO_3^{2-} + 2H^+ + 2Cl^- \to 2Na^+ + 2Cl^- + H_2O + SO_2\]

Write down the net ionic equation

To find the net ionic equation, we can eliminate spectator ions, which are common on both sides of the equation. In this case, the spectator ions are 2Na^+ and 2Cl^-. Therefore, we are left with the net ionic equation: \[SO_3^{2-} + 2H^+ \to H_2O + SO_2\] In conclusion, the balanced chemical equation for this reaction is: \[Na_2SO_3 + 2HCl \to 2NaCl + H_2O + SO_2\] The complete ionic equation is: \[2Na^+ + SO_3^{2-} + 2H^+ + 2Cl^- \to 2Na^+ + 2Cl^- + H_2O + SO_2\] The net ionic equation is: \[SO_3^{2-} + 2H^+ \to H_2O + SO_2\]

Key concepts

Chemical Reactions

A chemical reaction is a process where substances, known as reactants, transform into different substances called products. It involves breaking and forming of chemical bonds. An example of a chemical reaction is the mixing of sodium sulfite ( \(Na_2SO_3\)) with hydrochloric acid ( \(HCl\)), which produces sodium chloride ( \(NaCl\)), water ( \(H_2O\)), and sulfur dioxide ( \(SO_2\)).

In this reaction, the reactants undergoe a reaction to form the products. The reaction shows a change in the chemical composition of substances, indicating that a chemical reaction has occurred. It's vital to know that during these reactions, the total mass remains constant—this is due to the Law of Conservation of Mass, which states that matter cannot be created nor destroyed in a chemical reaction.

Ionic Equations

Ionic equations provide a deeper insight into the changes that occur during a reaction, especially reactions that involve ions in solution. Unlike a standard chemical equation that includes all reactants and products, an ionic equation breaks down aqueous ionic compounds into their respective ions. For instance, sodium sulfite ( \(Na_2SO_3\)) dissociates into two sodium ions ( \(2Na^+\)) and one sulfite ion ( \(SO_3^{2-}\)) in water. Similarly, hydrochloric acid dissociates into hydrogen ions ( \(H^+\)) and chloride ions ( \(Cl^-\)).

An ionic equation provides the actual species that are involved in the reaction, allowing us to understand the behavior of the ions before and after the reaction takes place. Ionic equations are particularly useful for precipitation reactions, acid-base reactions, and redox reactions.

Spectator Ions

Spectator ions are ions that are present in the reaction mixture but do not directly participate in the reaction. In other words, they remain unchanged and do not affect the overall chemical change that is taking place. For the reaction between sodium sulfite and hydrochloric acid, the spectator ions are sodium ( \(Na^+\)) and chloride ( \(Cl^-\)) ions.

These ions appear on both the reactant and product side of the complete ionic equation, indicating that they do not undergo any change. Spectator ions are crucial for writing net ionic equations because they are omitted to reflect the actual chemical change. Being able to identify and exclude the spectator ions from the net ionic reaction emphasizes the particles that partake in the transformation, streamlining the reaction to its essence.

Balancing Chemical Equations

Balancing chemical equations is essential to accurately represent the conservation of mass in a chemical reaction. Every element must have the same number of atoms on both the reactant and product sides of the equation. When balancing the reaction between sodium sulfite and hydrochloric acid, we ensure that the number of atoms of each element is equal on both sides.

To balance the given equation, we determine the stoichiometric coefficients that make the numbers of atoms of each element the same on both sides. This process leads us to the balanced chemical equation: \[Na_2SO_3 + 2HCl \rightarrow 2NaCl + H_2O + SO_2\]. Balancing equations helps us to adhere to the Law of Conservation of Mass, predict the amount of product formed, and calculate the required amount of reactants for a chemical reaction.