Question

Consider the following unbalanced chemical equation: \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(1)+\mathrm{O}_{2}(g) \rightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) (a) Balance this equation. (b) Classify the reaction type and explain. (c) Because one of the reactants is oxygen, what can you call this type of reaction?

Short answer

The balanced equation is \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\frac{11}{2}\mathrm{O}_{2}(g) \rightarrow 5\mathrm{CO}_{2}(g)+5\mathrm{H}_{2} \mathrm{O}(g)\). This reaction can be classified as a decomposition reaction, and since oxygen gas is one of the reactants, it can also be called an oxidation reaction.

Step-by-step solution

Write the unbalanced equation

First, let's write down the unbalanced chemical equation, which is: \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\mathrm{O}_{2}(g) \rightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\)

Count the number of atoms on both sides

Now we will count the number of atoms of each element on both sides of the equation. Left-hand side: 5C, 10H, 4O Right-hand side: 1C, 2H, 3O

Balance the equation

We'll balance the equation by adjusting the coefficients for each species: First, balance the carbon atoms (C) by adding the coefficient 5 to \(\mathrm{CO}_{2}\): \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\mathrm{O}_{2}(g) \rightarrow 5\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) Now we have: Left-hand side: 5C, 10H, 4O | Right-hand side: 5C, 2H, 10O Next, balance the hydrogen atoms (H) by adding the coefficient 5 to \(\mathrm{H}_{2}\mathrm{O}\): \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\mathrm{O}_{2}(g) \rightarrow 5\mathrm{CO}_{2}(g)+5\mathrm{H}_{2} \mathrm{O}(g)\) Now we have: Left-hand side: 5C, 10H, 4O | Right-hand side: 5C, 10H, 15O Finally, balance the oxygen atoms (O) by adding the coefficient \(\frac{11}{2}\) to \(\mathrm{O}_{2}\): \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\frac{11}{2}\mathrm{O}_{2}(g) \rightarrow 5\mathrm{CO}_{2}(g)+5\mathrm{H}_{2} \mathrm{O}(g)\) Now we have: Left-hand side: 5C, 10H, 15O; Right-hand side = 5C, 10H, 15O. The equation is now balanced. #b) Classifying the reaction type and explanation#

Examine the reactants and products

In order to classify the reaction type, we need to analyze the reactants and products. The given reaction is: \(\mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l)+\frac{11}{2}\mathrm{O}_{2}(g) \rightarrow 5\mathrm{CO}_{2}(g)+5\mathrm{H}_{2} \mathrm{O}(g)\)

Identify the reaction type

This reaction involves the breakdown of a compound (in this case, \(\mathrm{C}_{5}\mathrm{H}_{10}\mathrm{O}_{2}\)) into simpler substances (\(\mathrm{CO}_{2}\) and \(\mathrm{H}_{2}\mathrm{O}\)). Therefore, this reaction can be classified as a decomposition reaction. #c) A name for this type of reaction that includes oxygen as one of the reactants#

Consider the presence of oxygen in the reaction

In the given reaction, there is a presence of oxygen gas as one of the reactants (\(\mathrm{O}_{2}\)), which reacts with the compound to produce simpler products. This type of reaction can be called an oxidation reaction, as the oxygen gas is responsible for oxidizing other reactants involved.

Key concepts

Understanding Chemical Reaction Types

Chemical reactions are processes where the identity of substances changes, as reactant molecules are transformed into product molecules through the breaking and formation of chemical bonds. Understanding the types of chemical reactions is crucial for predicting products, understanding reaction mechanisms, and mastering stoichiometry.

There are several types of chemical reactions including synthesis, decomposition, single replacement, double replacement, combustion, and oxidation-reduction (redox) reactions. Synthesis reactions involve combining elements or compounds to form a more complex molecule. Decomposition reactions, on the other hand, involve breaking down a compound into simpler substances. Single replacement reactions see one element being swapped out of a compound by another, while in double replacement reactions, ions in two compounds switch places. Combustion reactions typically involve a hydrocarbon reacting with oxygen to produce carbon dioxide and water, releasing energy in the process. Finally, redox reactions involve the transfer of electrons between species, resulting in changes in oxidation states.

Decomposition Reactions Explained

Decomposition reactions occur when a single compound breaks down into two or more simpler substances. This type of reaction is often characterized by an input of energy, such as heat, light, or electricity, to break the chemical bonds within the compound. For example, the decomposition of water into hydrogen and oxygen gases through electrolysis is a classic case.

In the context of balancing chemical equations, identifying a decomposition reaction helps us determine the products and the proportions in which they are formed. For the given problem, \( \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l) \) decomposes into \( \mathrm{CO}_{2}(g) \) and \( \mathrm{H}_{2} \mathrm{O}(g) \), initiating the balancing process with the knowledge that the original compound is losing its complexity, breaking into carbon dioxide and water vapor.

Oxidation Reactions and Their Significance

Oxidation reactions involve the gain of oxygen or loss of hydrogen by a substance. These reactions are crucial in chemical processes like respiration and combustion. In the broader context, oxidation refers to the loss of electrons, while reduction refers to the gain of electrons in a chemical reaction; together these closely related processes form what’s known as redox reactions.

Oxidation can occur with the introduction of oxygen from the atmosphere, which is often the case in combustion reactions, or it can be a part of cellular respiration in living organisms, where glucose is oxidized to produce carbon dioxide, water, and energy. In the exercise, the presence of \( \mathrm{O}_{2}(g) \) as a reactant that reacts with \( \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{O}_{2}(l) \) to yield \( \mathrm{CO}_{2}(g) \) and \( \mathrm{H}_{2} \mathrm{O}(g) \) indicates an oxidation reaction. By recognizing this, students can apply appropriate strategies to balance the chemical equation, acknowledge the transfer of electrons, and understand the energetic changes associated with the reaction.