Question

Describe and provide an example of a hydrocarbon combustion reaction.

Short answer

An example of a hydrocarbon combustion reaction is the combustion of methane: \( \text{CH}_4(g) + 2\text{O}_2(g) \rightarrow \text{CO}_2(g) + 2\text{H}_2\text{O}(l) \).

Step-by-step solution

Understand Hydrocarbon Combustion

Hydrocarbon combustion is a chemical reaction where a hydrocarbon (a compound consisting of hydrogen and carbon) reacts with oxygen to produce carbon dioxide, water, and energy in the form of heat or light. The general formula for complete combustion of hydrocarbon is: \[ \text{Hydrocarbon} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} \]

Write a Balanced Equation for Combustion of a Simple Hydrocarbon

For example, let's write the balanced chemical equation for the combustion of methane (CH4), which is a simple hydrocarbon. Given the general formula, the reaction for methane would be: \[ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \]To balance the equation, ensure that there are the same number of each type of atom on both sides of the reaction. In this equation, one carbon atom, four hydrogen atoms, and four oxygen atoms are balanced.

Example of Hydrocarbon Combustion

With the balanced equation, we can provide the example of the combustion of one molecule of methane reacting with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water: \[ \text{CH}_4(g) + 2\text{O}_2(g) \rightarrow \text{CO}_2(g) + 2\text{H}_2\text{O}(l) \]The states of matter are also indicated: (g) for gases and (l) for liquid.

Key concepts

Chemical Equations

Understanding chemical equations is a fundamental part of chemistry that describes the substances involved in a chemical reaction and their relative proportions. A chemical equation consists of reactants and products, depicted with their chemical formulas. For instance, the combustion of methane, a hydrocarbon, can be represented by a simple chemical equation:
\[ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \].
In this equation, \(\text{CH}_4\) (methane) and \(\text{O}_2\) (oxygen) are the reactants, while \(\text{CO}_2\) (carbon dioxide) and \(\text{H}_2\text{O}\) (water) are the products. The coefficients like (2 for \(\text{O}_2\)) denote the number of units or moles needed for the reaction to preserve mass and stochiometric balance.

Balancing Chemical Reactions

Balancing chemical reactions is as crucial as writing them. It's a meticulous skill involving ensuring that the number of atoms for each element involved in the reaction is equal on both sides—maintaining the law of conservation of mass. For example, when balancing the combustion reaction of methane, we confirm that there are equal numbers of carbon, hydrogen, and oxygen atoms before and after the reaction:
\[ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} \].
The final equation has 1 carbon on both sides, 4 hydrogens on both sides, and 4 oxygens on both sides, fulfilling the balance. To students, it's like a puzzle where coefficients are strategically placed to balance the equation without altering the substances involved.

Hydrocarbons

Hydrocarbons are organic compounds composed exclusively of hydrogen and carbon atoms. These compounds form the basis of fossil fuels and can range from simple molecules like methane (\(\text{CH}_4\)) to complex structures like ethane, propane, and butane.

Classification of Hydrocarbons

Hydrocarbons are classified into alkanes, alkenes, and alkynes, based on the types of bonds between carbon atoms - single, double, or triple bonds respectively. The combustion of hydrocarbons is a significant energy source, although it also produces greenhouse gases, primarily carbon dioxide.

Combustion Reactions

Combustion reactions are a type of exothermic reaction where a substance combines with oxygen, releasing energy in the form of heat and light. In the context of hydrocarbons, combustion leads to the formation of carbon dioxide and water as products.

Complete and Incomplete Combustion

Complete combustion occurs when there is ample oxygen, ensuring hydrocarbons are converted fully into \(\text{CO}_2\) and \(\text{H}_2\text{O}\). Incomplete combustion happens with limited oxygen supply, yielding not only carbon dioxide and water but also carbon monoxide and soot (carbon). The balanced equation for methane's complete combustion reflects the theory behind it:
\[ \text{CH}_4(g) + 2\text{O}_2(g) \rightarrow \text{CO}_2(g) + 2\text{H}_2\text{O}(l) \].