Select The Correct Answer.Which Coefficient Of $O _2$ Is Needed To Balance The Equation $C _3 H _8 + O _2 \rightarrow 3 CO _2 + 4 H _2 O$?A. 2 B. 3 C. 5 D. 6
Understanding the Basics of Balancing Chemical Equations
Balancing chemical equations is a crucial concept in chemistry that helps us understand the stoichiometry of chemical reactions. It involves adding coefficients to the reactants or products to ensure that the number of atoms of each element is the same on both sides of the equation. In this article, we will focus on balancing the equation for the combustion of propane (C3H8) with oxygen (O2).
The Unbalanced Equation
The unbalanced equation for the combustion of propane is:
C3H8 + O2 → 3CO2 + 4H2O
Step 1: Count the Number of Atoms of Each Element
To balance the equation, we need to count the number of atoms of each element on both sides of the equation.
| Element | Number of Atoms on the Left Side | Number of Atoms on the Right Side |
|---|---|---|
| C | 3 | 3 |
| H | 8 | 8 |
| O | 2 | 8 |
Step 2: Balance the Carbon Atoms
Since there are 3 carbon atoms on both sides of the equation, the carbon atoms are already balanced.
Step 3: Balance the Hydrogen Atoms
There are 8 hydrogen atoms on both sides of the equation, so the hydrogen atoms are also balanced.
Step 4: Balance the Oxygen Atoms
There are 2 oxygen atoms on the left side of the equation, but 8 oxygen atoms on the right side. To balance the oxygen atoms, we need to add a coefficient in front of O2.
The Correct Coefficient of O2
Let's try adding a coefficient of 5 in front of O2:
C3H8 + 5O2 → 3CO2 + 4H2O
Now, let's count the number of oxygen atoms on both sides of the equation:
| Element | Number of Atoms on the Left Side | Number of Atoms on the Right Side |
|---|---|---|
| C | 3 | 3 |
| H | 8 | 8 |
| O | 10 | 8 |
We still have 2 extra oxygen atoms on the left side of the equation. To balance the oxygen atoms, we need to add a coefficient of 2 in front of H2O:
C3H8 + 5O2 → 3CO2 + 8H2O
Now, let's count the number of oxygen atoms on both sides of the equation:
| Element | Number of Atoms on the Left Side | Number of Atoms on the Right Side |
|---|---|---|
| C | 3 | 3 |
| H | 8 | 8 |
| O | 10 | 10 |
The oxygen atoms are now balanced.
Conclusion
In conclusion, the correct coefficient of O2 needed to balance the equation C3H8 + O2 → 3CO2 + 4H2O is 5. This is because we need to add a coefficient of 5 in front of O2 to balance the oxygen atoms on both sides of the equation.
Answer
The correct answer is:
A. 5
Additional Tips and Tricks
- When balancing chemical equations, it's essential to count the number of atoms of each element on both sides of the equation.
- Start by balancing the elements that appear only once on each side of the equation.
- Use coefficients to balance the elements that appear multiple times on each side of the equation.
- Check your work by counting the number of atoms of each element on both sides of the equation.
Common Mistakes to Avoid
- Don't forget to count the number of atoms of each element on both sides of the equation.
- Avoid adding coefficients that are not necessary to balance the equation.
- Make sure to check your work by counting the number of atoms of each element on both sides of the equation.
Real-World Applications
Balancing chemical equations has numerous real-world applications, including:
- Stoichiometry: Balancing chemical equations is essential for understanding the stoichiometry of chemical reactions.
- Chemical Reactions: Balancing chemical equations helps us understand the products and reactants of chemical reactions.
- Chemical Synthesis: Balancing chemical equations is crucial for designing and optimizing chemical synthesis reactions.
Conclusion
Q: What is the purpose of balancing chemical equations?
A: The purpose of balancing chemical equations is to ensure that the number of atoms of each element is the same on both sides of the equation. This is essential for understanding the stoichiometry of chemical reactions and for designing and optimizing chemical synthesis reactions.
Q: How do I know if a chemical equation is balanced?
A: A chemical equation is balanced if the number of atoms of each element is the same on both sides of the equation. You can check if a chemical equation is balanced by counting the number of atoms of each element on both sides of the equation.
Q: What is the difference between a balanced and unbalanced chemical equation?
A: A balanced chemical equation has the same number of atoms of each element on both sides of the equation, while an unbalanced chemical equation has a different number of atoms of each element on both sides of the equation.
Q: How do I balance a chemical equation?
A: To balance a chemical equation, follow these steps:
- Count the number of atoms of each element on both sides of the equation.
- Start by balancing the elements that appear only once on each side of the equation.
- Use coefficients to balance the elements that appear multiple times on each side of the equation.
- Check your work by counting the number of atoms of each element on both sides of the equation.
Q: What is a coefficient in a chemical equation?
A: A coefficient is a number that is placed in front of a formula to indicate the number of molecules of that substance that are involved in the reaction.
Q: How do I determine the correct coefficient for a chemical equation?
A: To determine the correct coefficient for a chemical equation, follow these steps:
- Count the number of atoms of each element on both sides of the equation.
- Determine the number of molecules of each substance that are involved in the reaction.
- Use the number of molecules to determine the correct coefficient for each substance.
Q: What is the difference between a mole and a molecule?
A: A mole is a unit of measurement that represents 6.022 x 10^23 particles (atoms or molecules), while a molecule is a group of atoms that are chemically bonded together.
Q: How do I use a mole to balance a chemical equation?
A: To use a mole to balance a chemical equation, follow these steps:
- Count the number of moles of each substance that are involved in the reaction.
- Use the number of moles to determine the correct coefficient for each substance.
- Check your work by counting the number of atoms of each element on both sides of the equation.
Q: What are some common mistakes to avoid when balancing chemical equations?
A: Some common mistakes to avoid when balancing chemical equations include:
- Forgetting to count the number of atoms of each element on both sides of the equation.
- Adding coefficients that are not necessary to balance the equation.
- Not checking your work by counting the number of atoms of each element on both sides of the equation.
Q: How do I know if a chemical equation is reversible?
A: A chemical equation is reversible if it can proceed in both the forward and reverse directions. This is indicated by a double arrow (⇌) between the reactants and products.
Q: What is the difference between a reversible and irreversible chemical equation?
A: A reversible chemical equation can proceed in both the forward and reverse directions, while an irreversible chemical equation can only proceed in one direction.
Q: How do I determine if a chemical equation is reversible or irreversible?
A: To determine if a chemical equation is reversible or irreversible, follow these steps:
- Look for a double arrow (⇌) between the reactants and products.
- Check if the equation can proceed in both the forward and reverse directions.
- If the equation can proceed in both directions, it is reversible. If it can only proceed in one direction, it is irreversible.
Conclusion
In conclusion, balancing chemical equations is a crucial concept in chemistry that helps us understand the stoichiometry of chemical reactions. By following the steps outlined in this article, you can balance chemical equations with ease. Remember to count the number of atoms of each element on both sides of the equation, start by balancing the elements that appear only once on each side of the equation, and use coefficients to balance the elements that appear multiple times on each side of the equation.