Question

Write a chemical equation for solid zinc hydrogen carbonate decomposing to yield solid zinc carbonate, water, and carbon dioxide gas.

Short answer

The balanced equation is: \[ \text{Zn(HCO}_3\text{)}_2 \rightarrow \text{ZnCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]

Step-by-step solution

Understand the Reactants and Products

We start with the decomposition of solid zinc hydrogen carbonate. The reactants and products involved are solid zinc hydrogen carbonate as the reactant, and the products are solid zinc carbonate, water, and carbon dioxide gas.

Write the Chemical Formulas

Solid zinc hydrogen carbonate is represented as \( \text{Zn(HCO}_3\text{)}_2 \). The products are solid zinc carbonate \( \text{ZnCO}_3 \), water \( \text{H}_2\text{O} \), and carbon dioxide gas \( \text{CO}_2 \).

Construct the Unbalanced Equation

Write the unbalanced chemical equation for the decomposition of zinc hydrogen carbonate: \[ \text{Zn(HCO}_3\text{)}_2 \rightarrow \text{ZnCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]

Balance the Chemical Equation

Balance the equation by ensuring the same number of each type of atom on both sides. For zinc, carbon, hydrogen, and oxygen, the balanced equation is: \[ \text{Zn(HCO}_3\text{)}_2 \rightarrow \text{ZnCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \] This equation is already balanced as written; one zinc, two carbon, three oxygen, and two hydrogen atoms appear on both sides.

Key concepts

Chemical Equations

Chemical equations are vital for representing chemical reactions. They use chemical symbols and formulas to describe the substances involved in a reaction. Think of chemical equations as the language of chemistry, where

• Reactants are the starting substances, shown on the left side.
• Products are the newly formed substances, located on the right side of the equation.

An arrow () points from reactants to products, symbolizing the transformation that occurs in the reaction. Each element in the equation must be represented using its chemical symbol. Keeping track of these is essential for balancing the equation later on.
For example, in the decomposition of zinc hydrogen carbonate: the equation initially looks like this: \[ \text{Zn(HCO}_3\text{)}_2 \rightarrow \text{ZnCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]
This equation shows the unbalanced state of reactants and products before adjusting for equal numbers of atoms on both sides of the equation.

Decomposition Reaction

A decomposition reaction is a type of chemical reaction where a single compound breaks down into two or more simpler substances. This type of reaction is generally represented as:

• One reactant yielding multiple products.
• Occurs when a compound splits or decomposes.

In our exercise, we are looking into the decomposition of zinc hydrogen carbonate, where one compound breaks down to form solid zinc carbonate, water, and carbon dioxide gas. This reaction is interesting because:

• The original compound is more complex, containing more elements combined together.
• Each product is simpler in structure and composition compared to the original reactant.

It's essential to understand that decomposition reactions often involve a source of energy like heat or light to break the bonds in the compound. These reactions are very common in everyday chemical processes, such as the breakdown of food in the body or the formation of rust.

Balancing Equations

Balancing chemical equations is essential for accurately representing the conservation of mass in chemical reactions. In a balanced equation, the number of atoms for each element is the same on both sides of the equation. This ensures that the matter is neither created nor destroyed during the reaction. Balancing involves:

• Counting the atoms of each element in both the reactants and products.
• Adjusting coefficients to equalize the atom count on each side of the equation.

For the decomposition of zinc hydrogen carbonate: \[ \text{Zn(HCO}_3\text{)}_2 \rightarrow \text{ZnCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]
You will notice the number of each atom on both sides of the equation is already equal. One zinc atom, two carbon atoms, four oxygen atoms, and two hydrogen atoms are present in equal quantities. It's critical to start balancing equations with the substance that appears the most complex and adjust the simplest substances last. This order of operations helps to efficiently balance even complicated chemical equations.