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Writing and Balancing Chemical Equations

4.1 Writing and Balancing Chemical Equations

How to Balance: The Trial-and-Error Method

1. Write the correct formulas for reactants and products.
2. Count the atoms of each element on both sides.
3. Use coefficients to balance elements one at a time. Tip: Leave Oxygen and Hydrogen for last.

✏️ Step-by-Step Example: Metabolism of Ethanol
Problem: Balance the equation for the combustion of ethanol (alcohol) in the body:

C2H5OH + O2 ➞ CO2 + H2O

Click for Step-by-Step Logic
  1. Carbon: 2 on left, 1 on right. Put a "2" in front of CO2.
  2. Hydrogen: 6 on left (5+1), 2 on right. Put a "3" in front of H2O.
  3. Oxygen: Now you have (2*2) + 3 = 7 on the right. On the left, you have 1 (in ethanol). You need 6 more. Put a "3" in front of O2.
  4. Final Result: C2H5OH + 3O2 ➞ 2CO2 + 3H2O