Question

For a chemical reaction to take place, some or all chemical bonds in the reactants must break, and new chemical bonds must form among the participating atoms to create the products. Write a simple chemical equation of your own choice, and list the bonds that must be broken and the bonds that must form for the reaction to take place.

Short answer

The synthesis of water from hydrogen and oxygen can be represented by the chemical equation: \(2H_2 + O_2 \longrightarrow 2H_2O\). In this reaction, 2 H-H bonds and 1 O=O bond must be broken, while 4 O-H bonds are formed to create the product, water.

Step-by-step solution

Choose a simple chemical reaction

We will use the synthesis of water from hydrogen and oxygen as our example. The chemical equation for this reaction is: \(2H_2 + O_2 \longrightarrow 2H_2O\)

Identify the reactants and products

In this reaction, the reactants are hydrogen gas (H₂) and oxygen gas (O₂), and the product is water (H₂O).

Determine the bonds broken and formed

In the reactant side, there are two H-H bonds in hydrogen gas molecules and one O=O double bond in the oxygen gas molecule. These bonds must be broken for the reaction to occur. In the product side, four O-H bonds are formed in the two water molecules. So, for this reaction to take place, the following bonds need to be broken and formed: - Break: 2 H-H bonds and 1 O=O bond - Form: 4 O-H bonds

Key concepts

Chemical Bonds

Chemical bonds are the glue that holds atoms together in molecules and compounds. These bonds are formed when atoms share or transfer their electrons in efforts to achieve a complete outer shell, which is often energetically favorable. There are different types of chemical bonds:

• Covalent Bonds: These occur when two atoms share electrons equally or unequally. In our example of water synthesis, we see O-H covalent bonds being formed.
• Ionic Bonds: Instead of sharing, atoms in an ionic bond transfer electrons, usually resulting in one positively and one negatively charged ion.
• Metallic Bonds: These involve a "sea" of electrons shared amongst a network of atoms, typically metals.

Understanding these bonds is crucial to deciphering how chemical reactions proceed. In the synthesis of water, bonds within the reactants must break first. These are 2 H-H bonds for hydrogen, and the O=O double bond for oxygen. Upon breaking, new bonds form, specifically 4 O-H bonds in water molecules. This transformation from breaking and forming bonds is what drives chemical reactions.

Synthesis Reaction

A synthesis reaction, sometimes called a composition reaction, involves combining smaller molecules or elements to create a more complex compound. This kind of reaction can be represented by the general formula:

• \[A + B \rightarrow AB\]

In our water synthesis example, hydrogen and oxygen gases react to form water.
It's a perfect showcase because it involves simple reactants, making it easier to understand the principle.
Synthesis reactions are very common in nature and industrial processes. They're the backbone of creating countless compounds from basic building blocks. With water synthesis, it’s important to note the energy change: the reaction releases energy, classifying it as exothermic. This is a characteristic of many synthesis reactions. They not only form new bonds but often lead to a release of energy as the products are typically more stable than the reactants.

Reactants and Products

In any chemical reaction, the substances you start with are called "reactants," and the new substances formed are called "products." Reactants undergo chemical changes and form the products.
The equation must balance, meaning the number of atoms for each element needs to be the same on both sides of the equation.

• Reactants: In our example, these are two molecules of hydrogen gas \(2H_2\) and one molecule of oxygen gas \(O_2\).
• Products: The reaction yields two molecules of water \(2H_2O\).

Maintaining a balanced equation ensures the law of conservation of mass is respected in chemical reactions.
This means no atoms are lost; they are simply rearranged.
Observing this principle in the synthesis of water, we see four hydrogen atoms and two oxygen atoms on both sides of the chemical equation, emphasizing the transformation while maintaining atomic integrity.