Question

Choose a chemical substance with which you are familiar, and give an example of a chemical change that might take place to the substance.

Short answer

The chosen chemical substance is hydrogen peroxide (H2O2), and an example of a chemical change is its decomposition into water (H2O) and oxygen gas (O2). The balanced chemical equation for this reaction is: \(2H_2O_2 \rightarrow 2H_2O + O_2\).

Step-by-step solution

Choose a Familiar Chemical Substance

We will choose Hydrogen Peroxide (H2O2) as the example chemical substance.

Describe a Chemical Change

A common chemical change involving hydrogen peroxide is its decomposition into water (H2O) and oxygen gas (O2). This decomposition reaction can be hastened by exposure to light, heat, or a catalyst, such as manganese dioxide (MnO2).

Write the Balanced Chemical Equation

The balanced chemical equation for the decomposition of hydrogen peroxide is: \(2H_2O_2 \rightarrow 2H_2O + O_2\) This equation shows that two molecules of hydrogen peroxide (H2O2) decompose into two molecules of water (H2O) and one molecule of oxygen gas (O2).

Summary

In this example, the familiar chemical substance chosen is hydrogen peroxide (H2O2), and the chemical change is its decomposition into water (H2O) and oxygen gas (O2). The balanced chemical equation for this process is: \(2H_2O_2 \rightarrow 2H_2O + O_2\)

Key concepts

Decomposition Reaction

A decomposition reaction is a type of chemical reaction where one substance breaks down into two or more simpler substances. One of the characteristics of these reactions is that they often require an external energy source, such as heat, light, or electricity, to start. In a typical decomposition reaction, a single compound, known as the reactant, splits into two or more products. For example, when hydrogen peroxide decomposes, it breaks down into water and oxygen gas. This type of chemical change is the opposite of a combination reaction, where simpler substances combine to form a more complex compound.

Balanced Chemical Equation

A balanced chemical equation is an expression that shows the identities and relative amounts of the reactants and products involved in a chemical reaction. Balancing equations is crucial because it reflects the conservation of mass, meaning matter cannot be created or destroyed. When balancing a chemical equation, it is important to ensure that the number of each type of atom is conserved on both sides of the equation. For the decomposition of hydrogen peroxide, the balanced chemical equation is:

• \(2H_2O_2 \rightarrow 2H_2O + O_2\)

This indicates that two molecules of hydrogen peroxide yield two molecules of water and one molecule of oxygen, conserving the number of each type of atom involved in the reaction.

Catalyst in Chemistry

A catalyst is a substance that speeds up a chemical reaction without itself being consumed in the process. It achieves this by lowering the activation energy needed for the reaction to proceed, allowing it to happen more quickly or at lower temperatures. Catalysts work by providing an alternative pathway for the reaction. In the decomposition of hydrogen peroxide, catalysts such as manganese dioxide (MnO2) or potassium iodide (KI) are often used. These catalysts allow hydrogen peroxide to decompose more rapidly into water and oxygen gas compared to when no catalyst is present. Catalysts are crucial in many industrial and biological processes, where they play a key role in increasing efficiency and reducing energy consumption.

Hydrogen Peroxide Decomposition

Hydrogen peroxide decomposition is a common and well-known reaction where hydrogen peroxide (\(H_2O_2\)) breaks down into water (\(H_2O\)) and oxygen gas (\(O_2\)). This reaction can happen naturally over time, especially when exposed to light and heat. However, it occurs much faster in the presence of a catalyst. The reaction is particularly notable because it releases oxygen gas, which is visible as bubbles, and is an exothermic process, releasing heat. Because of these properties, hydrogen peroxide decomposition has practical applications such as in cleaning and disinfecting surfaces, where the release of oxygen helps to sanitize by breaking down organic material.