Equation For The Combustion Of Ethane

The combustion of ethane is a fundamental chemical process, releasing energy in the form of heat and light, making it widely used in various industrial and domestic applications. Understanding the balanced chemical equation for this reaction is crucial for stoichiometric calculations, optimizing combustion processes, and minimizing environmental impact.

Understanding Combustion Reactions

Combustion is a chemical process involving rapid reaction between a substance with an oxidant, usually oxygen, to produce heat and light. This is an exothermic reaction, meaning it releases energy in the form of heat. Complete combustion occurs when there's an excess of oxygen, leading to the formation of carbon dioxide ($CO_2$) and water ($H_2O$) as the primary products. Incomplete combustion, on the other hand, happens when there is a limited supply of oxygen, resulting in the formation of carbon monoxide ($CO$), soot (carbon), and other byproducts in addition to carbon dioxide and water.

Ethane: A Simple Hydrocarbon

Ethane ($C_2H_6$) is a simple alkane consisting of two carbon atoms and six hydrogen atoms. It is a colorless, odorless gas at room temperature and pressure. Ethane is a significant component of natural gas and is used as a feedstock in the petrochemical industry for producing ethylene and other valuable chemicals.

The Unbalanced Equation for Ethane Combustion

Before diving into the balanced equation, let's first write the unbalanced equation for the combustion of ethane:

$C_2H_6 + O_2 \rightarrow CO_2 + H_2O$

This equation tells us that ethane reacts with oxygen to produce carbon dioxide and water. However, the number of atoms of each element is not the same on both sides of the equation. Therefore, it needs to be balanced to satisfy the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.

Balancing the Equation for Ethane Combustion: A Step-by-Step Guide

Balancing chemical equations involves adjusting the coefficients in front of each chemical formula until the number of atoms of each element is the same on both sides of the equation. Here's a systematic approach to balancing the ethane combustion equation:

Step 1: Count the Atoms

First, count the number of atoms of each element on both sides of the unbalanced equation:

• Reactants:
  • Carbon (C): 2
  • Hydrogen (H): 6
  • Oxygen (O): 2
• Products:
  • Carbon (C): 1
  • Hydrogen (H): 2
  • Oxygen (O): 3

Step 2: Balance Carbon Atoms

To balance the carbon atoms, we need to have the same number of carbon atoms on both sides of the equation. Since there are 2 carbon atoms on the reactant side and only 1 on the product side, we place a coefficient of 2 in front of $CO_2$:

$C_2H_6 + O_2 \rightarrow 2CO_2 + H_2O$

Now, the number of carbon atoms is balanced:

• Reactants:
  • Carbon (C): 2
• Products:
  • Carbon (C): 2

Step 3: Balance Hydrogen Atoms

Next, we balance the hydrogen atoms. There are 6 hydrogen atoms on the reactant side and only 2 on the product side. To balance the hydrogen atoms, we place a coefficient of 3 in front of $H_2O$:

$C_2H_6 + O_2 \rightarrow 2CO_2 + 3H_2O$

Now, the number of hydrogen atoms is balanced:

• Reactants:
  • Hydrogen (H): 6
• Products:
  • Hydrogen (H): 6

Step 4: Balance Oxygen Atoms

Finally, we balance the oxygen atoms. On the product side, we have 2 oxygen atoms in each $CO_2$ molecule and 1 oxygen atom in each $H_2O$ molecule. With the coefficients we've added, there are now:

• 2 $CO_2$ molecules, containing a total of $2 \times 2 = 4$ oxygen atoms
• 3 $H_2O$ molecules, containing a total of $3 \times 1 = 3$ oxygen atoms

So, the total number of oxygen atoms on the product side is $4 + 3 = 7$.

On the reactant side, we have $O_2$, which contains 2 oxygen atoms. To balance the oxygen atoms, we need to find a coefficient for $O_2$ that will give us 7 oxygen atoms. We can do this by using a fractional coefficient:

$C_2H_6 + \frac{7}{2}O_2 \rightarrow 2CO_2 + 3H_2O$

Now, the number of oxygen atoms is balanced:

• Reactants:
  • Oxygen (O): $2 \times \frac{7}{2} = 7$
• Products:
  • Oxygen (O): $(2 \times 2) + (3 \times 1) = 7$

Step 5: Remove the Fraction (Optional)

While the equation is technically balanced, it's common practice to remove fractions by multiplying the entire equation by the denominator. In this case, we multiply the entire equation by 2:

$2(C_2H_6 + \frac{7}{2}O_2 \rightarrow 2CO_2 + 3H_2O)$

This gives us the final balanced equation:

$2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O$

The Balanced Equation for Ethane Combustion

The balanced chemical equation for the complete combustion of ethane is:

$2C_2H_6(g) + 7O_2(g) \rightarrow 4CO_2(g) + 6H_2O(g)$

In this equation:

• $2C_2H_6(g)$ represents two moles of ethane gas.
• $7O_2(g)$ represents seven moles of oxygen gas.
• $4CO_2(g)$ represents four moles of carbon dioxide gas.
• $6H_2O(g)$ represents six moles of water vapor.

Stoichiometric Implications

The balanced equation provides valuable information about the stoichiometry of the reaction. It tells us the molar ratios of reactants and products involved in the combustion of ethane. For example:

• 2 moles of ethane require 7 moles of oxygen for complete combustion.
• The combustion of 2 moles of ethane produces 4 moles of carbon dioxide and 6 moles of water.

These stoichiometric ratios are essential for calculating the amount of reactants needed and the amount of products formed in a given reaction. They are also crucial for optimizing combustion processes and minimizing the formation of pollutants.

Energy Considerations

The combustion of ethane is an exothermic reaction, releasing a significant amount of energy in the form of heat. The amount of heat released is known as the enthalpy change of combustion ($\Delta H_c$), which is typically expressed in kilojoules per mole (kJ/mol).

The standard enthalpy change of combustion ($\Delta H_c^\circ$) for ethane is approximately -1560 kJ/mol. This means that when 1 mole of ethane is completely combusted under standard conditions (298 K and 1 atm), 1560 kJ of heat is released.

The negative sign indicates that the reaction is exothermic. The enthalpy change of combustion can be used to calculate the amount of heat released or absorbed in a chemical reaction, as well as to determine the energy efficiency of a fuel.

Practical Applications

The combustion of ethane has numerous practical applications in various industries and domestic settings:

• Power Generation: Ethane is a component of natural gas, which is widely used in power plants to generate electricity. The combustion of natural gas produces heat, which is used to generate steam that drives turbines connected to generators.
• Heating: Natural gas is also used for heating homes and buildings. Furnaces and boilers burn natural gas to produce heat, which is distributed throughout the building via ducts or pipes.
• Industrial Processes: Ethane is used as a feedstock in the petrochemical industry for producing ethylene, a key building block for plastics and other chemical products. Ethylene is produced by steam cracking of ethane at high temperatures.
• Transportation: While ethane itself is not commonly used as a transportation fuel, it can be converted into other fuels, such as ethylene, which can be used to produce gasoline additives and other transportation fuels.

Environmental Impact

While the combustion of ethane is a clean energy source compared to other fossil fuels, it still contributes to air pollution and greenhouse gas emissions. The main environmental concerns associated with ethane combustion are:

• Carbon Dioxide Emissions: The combustion of ethane produces carbon dioxide ($CO_2$), a greenhouse gas that contributes to climate change. Reducing carbon dioxide emissions from ethane combustion is essential for mitigating the effects of climate change.
• Air Pollution: Incomplete combustion of ethane can produce carbon monoxide ($CO$), a toxic gas that can cause health problems. It can also produce soot (carbon particles) and other air pollutants that contribute to smog and respiratory problems.
• Water Vapor Emissions: The combustion of ethane produces water vapor ($H_2O$), which is also a greenhouse gas, although its impact on climate change is less significant compared to carbon dioxide.

Strategies for Minimizing Environmental Impact

Several strategies can be employed to minimize the environmental impact of ethane combustion:

• Improve Combustion Efficiency: Optimizing combustion processes can reduce the formation of carbon monoxide and other air pollutants. This can be achieved by ensuring an adequate supply of oxygen, maintaining proper temperature, and using advanced combustion technologies.
• Carbon Capture and Storage: Carbon capture and storage (CCS) technologies can capture carbon dioxide emissions from power plants and industrial facilities and store them underground, preventing them from entering the atmosphere.
• Renewable Energy Sources: Transitioning to renewable energy sources, such as solar, wind, and hydro, can reduce the reliance on fossil fuels like ethane and decrease greenhouse gas emissions.
• Energy Efficiency: Improving energy efficiency in buildings, transportation, and industry can reduce the overall demand for energy and decrease the amount of ethane that needs to be combusted.

Common Mistakes in Balancing Combustion Equations

Balancing combustion equations can be tricky, and several common mistakes can lead to incorrect results. Here are some of the most common mistakes to avoid:

• Not Counting All Atoms: Ensure that you count all atoms of each element on both sides of the equation. Double-check your work to avoid errors.
• Changing Subscripts: Never change the subscripts in the chemical formulas. Changing the subscripts changes the identity of the compound. Only change the coefficients in front of the chemical formulas.
• Not Reducing to Simplest Whole Number Ratio: After balancing the equation, make sure that the coefficients are in the simplest whole number ratio. If you can divide all the coefficients by a common factor, do so.
• Ignoring Polyatomic Ions: When balancing equations involving polyatomic ions (e.g., $SO_4^{2-}$, $NO_3^-$), treat the polyatomic ion as a single unit if it appears on both sides of the equation.
• Forgetting to Balance Oxygen Last: Oxygen is often the last element to be balanced in combustion equations. Balancing oxygen last can simplify the process and reduce errors.

Advanced Considerations

Incomplete Combustion

Incomplete combustion occurs when there is insufficient oxygen for the reaction to proceed completely to carbon dioxide and water. In this case, products like carbon monoxide (CO) and soot (C) are also formed. The equation for incomplete combustion is more complex and can vary depending on the specific conditions. A general representation might look like:

$C_2H_6 + xO_2 \rightarrow yCO_2 + zCO + pH_2O + qC$

Where x, y, z, p, and q are coefficients that depend on the amount of oxygen available.

Influence of Temperature and Pressure

Temperature and pressure can significantly influence the combustion process. Higher temperatures generally lead to more complete combustion, while lower temperatures can result in incomplete combustion. Pressure also affects the reaction rate and the composition of the products.

Catalytic Combustion

Catalytic combustion involves the use of a catalyst to promote the reaction at lower temperatures. This can improve combustion efficiency and reduce emissions of pollutants. Catalysts such as platinum, palladium, and rhodium are commonly used in catalytic converters in automobiles to reduce emissions of carbon monoxide, hydrocarbons, and nitrogen oxides.

Conclusion

The combustion of ethane is a fundamental chemical process with significant practical applications. Balancing the chemical equation for this reaction is essential for stoichiometric calculations, optimizing combustion processes, and minimizing environmental impact. By following the step-by-step guide outlined in this article, you can confidently balance the equation for ethane combustion and understand its implications. Always remember to double-check your work and avoid common mistakes to ensure accurate results. Understanding the balanced equation, stoichiometric implications, energy considerations, and environmental impact of ethane combustion is crucial for making informed decisions about energy use and environmental sustainability.