Question

Write a balanced equation for each of the following combination reactions: (a) Nitrogen is heated with oxygen to form dinitrogen pentaoxide gas. (b) Chlorine is heated with oxygen to form dichlorine trioxide gas.

Short answer

(a) 2N₂ + 5O₂ → 2N₂O₅; (b) 2Cl₂ + 3O₂ → 2Cl₂O₃.

Step-by-step solution

Identify Reactants and Products (a)

In reaction (a), the reactants are nitrogen (N₂) and oxygen (O₂) gases. The product is dinitrogen pentaoxide (N₂O₅) gas.

Write Unbalanced Equation (a)

Write the unbalanced chemical equation for the reaction: N₂ + O₂ → N₂O₅.

Balance the Equation (a)

Count the number of atoms for each element on both sides. Balance one element at a time, starting with nitrogen: - Nitrogen: N₂ → N₂O₅ gives 2 N atoms on both sides, which is balanced. - Oxygen: To balance oxygen, we need 5 O atoms in the product, so we need 2.5 O₂ molecules. To deal with fractions, multiply all coefficients by 2: 2N₂ + 5O₂ → 2N₂O₅.

Identify Reactants and Products (b)

In reaction (b), the reactants are chlorine (Cl₂) and oxygen (O₂) gases. The product is dichlorine trioxide (Cl₂O₃) gas.

Write Unbalanced Equation (b)

Write the unbalanced chemical equation for the reaction: Cl₂ + O₂ → Cl₂O₃.

Balance the Equation (b)

Count the number of atoms for each element on both sides. Balance one element at a time: - Chlorine: Cl₂ → Cl₂O₃ gives 2 Cl atoms on both sides, which is balanced. - Oxygen: To balance oxygen, ensure the number of O atoms on both sides match the oxidation state. Assume 3 O atoms derive from 1.5 O₂ molecules, multiply all coefficients by 2: 2Cl₂ + 3O₂ → 2Cl₂O₃.

Key concepts

Balancing Equations

Balancing chemical equations is essential for accurately representing chemical reactions. Chemical equations showcase the transformation of reactants into products, and a balanced equation ensures the conservation of mass, where the number of atoms for each element is equal on both sides of the equation.

When balancing equations, follow these steps:

• Write the unbalanced equation with correct chemical formulas for the reactants and products.
• List the number of atoms of each element on both sides of the equation.
• Modify coefficients to make the number of atoms of each element equal on both sides. Focus on one element at a time.
• Use fractions if necessary, then multiply all coefficients to eliminate fractions.

In the exercise provided, we balanced two reactions involving oxygen gas (O₂), nitrogen (N₂), and chlorine (Cl₂). Balancing such equations ensures correct stoichiometric proportions are maintained, which is critical for understanding and predicting the outcome of chemical reactions.

Combination Reactions

Combination reactions, sometimes known as synthesis reactions, occur when two or more substances combine to form a single, more complex product.

Characteristics of combination reactions include:

• Two or more reactants, typically elements or simple compounds, unite to form one product.
• The product is usually a compound that has a different composition than the reactants.

In the original exercise, both reactions (a and b) are examples of combination reactions:
- Reaction (a): Nitrogen combines with oxygen to form dinitrogen pentaoxide gas.
- Reaction (b): Chlorine combines with oxygen to form dichlorine trioxide gas.

These reactions are fundamental in understanding how new compounds form. Recognizing these reactions helps in predicting products and balancing equations.

Oxidation State

The concept of oxidation state is important in determining how elements interact during a reaction. Oxidation states provide insight into the distribution of electrons among atoms in a molecule, which is fundamental for balancing equations involving redox processes.

Some key points about oxidation states include:

• They reflect the hypothetical charge an atom would have if all bonds were completely ionic.
• Oxidation states help identify changes occurring in redox (reduction-oxidation) reactions.

For example, in reaction (b): - Each oxygen atom typically has an oxidation state of -2. Similarly, chlorine in Cl₂O₃ can undergo multiple oxidation states.

Understanding oxidation states can facilitate the balancing of oxygen and other elements in chemical equations. Knowing that oxygen typically forms O₂ molecules helps predict how many atoms are required to balance equations thoroughly, as seen in the provided example.