Problem 26 - Chemistry Matter and Change

Question

Aqueous barium chloride and aqueous potassium carbonate react to produce solid barium carbonate and aqueous potassium chloride.

Step-by-Step Solution

Answer

The balanced chemical equation for the reaction between aqueous barium chloride (BaCl2) and aqueous potassium carbonate (K2CO3) is: \(BaCl_2(aq) + K_2CO_3(aq) \rightarrow BaCO_3(s) + 2KCl(aq)\) In this double replacement reaction, solid barium carbonate (BaCO3) and aqueous potassium chloride (2KCl) are the products.

Step 1: Barium chloride formula

The chemical formula for barium chloride is BaCl2, where Ba represents a Ba^(2+) ion and Cl represents a Cl^(-) ion.

Step 2: Potassium carbonate formula

The chemical formula for potassium carbonate is K2CO3, where K represents a K^(+) ion and CO3 represents a CO3^(2-) ion. #Step 2: Write and balance the chemical equation for the reaction#

Step 3: Double replacement

In a double replacement reaction, the cations and anions of the two reactants switch places to form new products: BaCl2(aq) + K2CO3(aq) → BaCO3(s) + 2KCl(aq) Here, Ba^(2+) and Cl^(-) switch places with K^(+) and CO3^(2-), respectively. The coefficients 1 and 2 are used to balance the equation. #Step 3: Identify the state of matter for each product#

Step 4: Barium carbonate state

The problem states that barium carbonate is a solid product, so we indicate this with an (s) after its formula.

Step 5: Potassium chloride state

The problem states that potassium chloride is an aqueous product, so we indicate this with an (aq) after its formula. #Final Answer: Balanced chemical equation with states of matter# The balanced chemical equation for the reaction between aqueous barium chloride and aqueous potassium carbonate is: BaCl2(aq) + K2CO3(aq) → BaCO3(s) + 2KCl(aq)

Key Concepts

Double Replacement Reaction

In chemistry, a double replacement reaction involves two compounds that exchange parts, forming two new compounds. These reactions typically occur in solutions where two ionic compounds swap components.

For example, in our exercise, barium chloride \(\text{BaCl}_2\) and potassium carbonate \(\text{K}_2\text{CO}_3\) undergo a double replacement reaction.

Here's how it works:

• The positive ions (cations) and negative ions (anions) from two different compounds switch places.
• In this case, Ba^(2+) from barium chloride trades places with K^(+) from potassium carbonate.
• The result is the formation of barium carbonate \(\text{BaCO}_3\) and potassium chloride \(\text{KCl}\).

This type of reaction is common in various chemical processes and can even be observed in everyday occurrences like certain cleaning products.

Balancing Chemical Equations

Balancing chemical equations is an essential skill in chemistry. It ensures that the same number of each type of atom is present on both sides of the equation. This balance adheres to the Law of Conservation of Mass, which states that mass cannot be created or destroyed in an ordinary chemical reaction.

For our example reaction: \[\text{BaCl}_2(\text{aq}) + \text{K}_2\text{CO}_3(\text{aq}) \rightarrow \text{BaCO}_3(\text{s}) + 2\text{KCl}(\text{aq})\]

• The equation starts with the same number of Ba, Cl, K, and CO atoms on both sides.
• By adding the coefficient "2" in front of \(\text{KCl}\), the equation becomes balanced.

This step ensures that the number of atoms for each element is equal on both sides, making the equation correct and reflecting the actual chemical change.

States of Matter

The states of matter in a chemical equation indicate the physical form each substance takes during the reaction. These states are crucial for understanding how substances interact in different phases.

In our reaction, we observe:

• Aqueous (aq) - Substances dissolved in water, such as barium chloride and potassium carbonate, are in aqueous form.
• Solid (s) - Barium carbonate precipitates out of the solution as a solid, indicated by (s).
• Another aqueous (aq) - Potassium chloride remains dissolved in water.

Understanding these states helps to visualize the reaction process and predict the conditions under which the reaction occurs. States of matter not only provide insight into solubility and precipitation but also help in determining reaction mechanisms.