Question

Write a balanced equation for each of the following decomposition reactions: (a) Silver hydrogen carbonate decomposes by heating to give solid silver carbonate, water, and carbon dioxide gas. (b) Nickel(II) hydrogen carbonate decomposes by heating to give nickel(II) carbonate, water, and carbon dioxide gas.

Short answer

(a) \( 2 \text{AgHCO}_3 \rightarrow \text{Ag}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2 \). (b) \( \text{Ni(HCO}_3)_2 \rightarrow \text{NiCO}_3 + 2 \text{H}_2\text{O} + 2 \text{CO}_2 \).

Step-by-step solution

Write the Reactants for Reaction (a)

For reaction (a), we start with silver hydrogen carbonate as the reactant. The chemical formula for silver hydrogen carbonate is \( \text{AgHCO}_3 \). This will be our starting substance.

Determine the Products for Reaction (a)

Upon decomposition, silver hydrogen carbonate will yield silver carbonate \( \text{Ag}_2\text{CO}_3 \), water \( \text{H}_2\text{O} \), and carbon dioxide \( \text{CO}_2 \).

Write the Unbalanced Equation for Reaction (a)

The reaction can be initially written as: \[ \text{AgHCO}_3 \rightarrow \text{Ag}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]

Balance the Chemical Equation for Reaction (a)

Balance the number of each type of atom on both sides of the equation:First, balance silver (Ag) by placing a coefficient of 2 in front of \( \text{AgHCO}_3 \):\[ 2 \text{AgHCO}_3 \rightarrow \text{Ag}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]Next, ensure that the number of each atom type matches on both sides. The equation is now balanced.

Write the Reactants for Reaction (b)

For reaction (b), we start with nickel(II) hydrogen carbonate as the reactant. The chemical formula for nickel(II) hydrogen carbonate is \( \text{Ni(HCO}_3)_2 \). It serves as the initial substance.

Determine the Products for Reaction (b)

The decomposition of nickel(II) hydrogen carbonate will yield nickel(II) carbonate \( \text{NiCO}_3 \), water \( \text{H}_2\text{O} \), and carbon dioxide \( \text{CO}_2 \).

Write the Unbalanced Equation for Reaction (b)

The initial equation for reaction (b) is:\[ \text{Ni(HCO}_3)_2 \rightarrow \text{NiCO}_3 + \text{H}_2\text{O} + \text{CO}_2 \]

Balance the Chemical Equation for Reaction (b)

Balance the equation by first counting the number of atoms:For water and carbon dioxide to balance the hydrogen carbonate, set up coefficients that balance oxygen and hydrogen: \[ \text{Ni(HCO}_3)_2 \rightarrow \text{NiCO}_3 + 2 \text{H}_2\text{O} + 2 \text{CO}_2 \]All atom types are now balanced.

Key concepts

Balancing Chemical Equations

Balancing chemical equations is an essential skill in chemistry that ensures the same number of each type of atom appears on both sides of the reaction equation. When a chemical reaction occurs, matter is neither created nor destroyed, which means that all atoms present in the reactants must be accounted for as products.

Here is how you can balance an equation:

• Start by writing down the unbalanced chemical equation based on the reactants and products involved in the reaction.
• Count the number of atoms for each element in both the reactants and products.
• Adjust coefficients (the numbers placed before compounds) to ensure the same number of each type of atom on both sides.
• Begin balancing with elements that appear in only one reactant and one product, then move to more complex ones.
• Check your work to make sure all atoms are balanced and that the total mass of the reactants equals the total mass of the products.

Balancing is like solving a puzzle—shift around the coefficients to make the equation work.

Chemical Formulas

Chemical formulas are a straightforward way to represent chemical substances. They show the types and numbers of atoms involved in a compound.

For instance, silver hydrogen carbonate is written as \( \text{AgHCO}_3 \). This formula tells us that each molecule consists of:

• One silver (Ag) atom.
• One hydrogen (H) atom.
• One carbon (C) atom.
• Three oxygen (O) atoms.

Understanding chemical formulas helps in predicting how substances will react. For nickel(II) hydrogen carbonate, the formula is \( \text{Ni(HCO}_3)_2 \), indicating:

• One nickel (Ni) atom in each molecule.
• Two sets of hydrogen carbonate \( \text{(HCO}_3) \), meaning two hydrogens, two carbons, and six oxygens in total.

Formulas provide a quick snapshot of a substance’s composition, crucial for writing and balancing chemical equations.

Decomposition Process

Decomposition reactions involve breaking down a single compound into simpler substances. This type of reaction typically occurs when you apply heat to the starting material.

For example:

• Silver hydrogen carbonate \( \text{AgHCO}_3 \) decomposes into silver carbonate \( \text{Ag}_2\text{CO}_3 \), water (\( \text{H}_2\text{O} \)), and carbon dioxide (\( \text{CO}_2 \)).
• Nickel(II) hydrogen carbonate \( \text{Ni(HCO}_3)_2 \) decomposes into nickel(II) carbonate \( \text{NiCO}_3 \), water, and carbon dioxide as well.

During decomposition, a single reactant breaks down into multiple products. It's important for creating new substances and is common in various chemical processes. By using heat or sometimes a catalyst, bonds in the molecule break, leading to new arrangements of atoms in different compounds.

The decomposition process is a reminder of the transformative nature of chemistry, where compounds come apart to form new ones.