Balancing chemical equations examples

📚 Quick Study Guide

• ⚛️ What is a Balanced Chemical Equation? A chemical equation where the number of atoms for each element in the reaction is the same for both the reactants and products.
• ⚖️ Why Balance? The Law of Conservation of Mass states that matter cannot be created or destroyed. Balancing ensures this law is upheld.
• 🔢 Steps to Balance:
  1. Write the unbalanced equation.
  2. Count the atoms of each element on both sides.
  3. Add coefficients (the numbers in front of the chemical formulas) to balance the number of atoms.
  4. Double-check that all atoms are balanced.
• 💡 Tips & Tricks:
  • Start with the most complex molecule.
  • Balance elements that appear only once on each side first.
  • If you get stuck, try balancing oxygen and hydrogen last.
  • Remember that coefficients multiply the entire molecule.
• ➗ Example:
  • Unbalanced: $H_2 + O_2 \rightarrow H_2O$
  • Balanced: $2H_2 + O_2 \rightarrow 2H_2O$

🧪 Practice Quiz

1. What coefficient is needed to balance the following equation: $N_2 + H_2 \rightarrow NH_3$?
1. 1, 2
2. 2, 3
3. 1, 3
4. 3, 2
2. Balance the following equation: $CH_4 + O_2 \rightarrow CO_2 + H_2O$. What is the coefficient in front of the $O_2$?
1. 1
2. 2
3. 3
4. 4
3. What law necessitates the balancing of chemical equations?
1. Law of Thermodynamics
2. Law of Conservation of Energy
3. Law of Conservation of Mass
4. Law of Definite Proportions
4. Which of the following equations is already balanced?
1. $2Na + Cl_2 \rightarrow 2NaCl$
2. $H_2 + O_2 \rightarrow H_2O$
3. $N_2 + H_2 \rightarrow NH_3$
4. $CH_4 + O_2 \rightarrow CO_2 + H_2O$
5. Balance the following equation: $KClO_3 \rightarrow KCl + O_2$. What is the coefficient in front of $KClO_3$?
1. 1
2. 2
3. 3
4. 4
6. What does a coefficient in a chemical equation represent?
1. The number of atoms in a molecule
2. The number of molecules of a substance
3. The charge of an ion
4. The mass of a substance
7. Balance: $C_2H_6 + O_2 \rightarrow CO_2 + H_2O$. What is the coefficient in front of $H_2O$?
1. 2
2. 3
3. 4
4. 6