How to Balance a Chemical Equation: 7 Steps (with Pictures)

Table of contents:

How to Balance a Chemical Equation: 7 Steps (with Pictures)
How to Balance a Chemical Equation: 7 Steps (with Pictures)

Video: How to Balance a Chemical Equation: 7 Steps (with Pictures)

Video: How to Balance a Chemical Equation: 7 Steps (with Pictures)
Video: Learning About Line Graphs 2024, November
Anonim

A chemical equation is a theoretical or written representation of what happens when a chemical reaction takes place. The law of conservation of mass states that no atoms can be created or destroyed in a chemical reaction, so the number of atoms in the reactants must balance the number of atoms in the products. Follow this guide to learn how to balance chemical equations.

Step

Image
Image

Step 1. Write down the equation given to you

For this example, you would use:

C3H8 + O2 H2O + CO2

Image
Image

Step 2. Write down the number of atoms you have on each side of the equation

Look at the index below next to each atom to find the number of atoms in the equation.

  • Left side: 3 carbons, 8 hydrogens, and 2 oxygens.
  • Right side: 1 carbon, 2 hydrogen, and 3 oxygen.
Image
Image

Step 3. Always leave the hydrogen and oxygen until the end of the calculation

This means you need to balance the carbon atoms first.

Step 4. Add a coefficient on the single carbon atom on the right side of the equation to balance with the 3 carbon atoms on the left side

C3H8 + O2 H2O + 3CO2

Image
Image
  • The coefficient 3 in front of the carbon symbol on the right side indicates 3 carbon atoms as the bottom index 3 on the left side indicates 3 carbon atoms.
  • In a chemical equation, you can change the coefficients, but never change the bottom index.

Step 5.

  • Next, balance the hydrogen atoms.

    You have 8 on the left side. So you need 8 on the right side.

    C3H8 + O2 4H2O + 3CO2

    Image
    Image
    • On the right, you're now adding 4 as a coefficient because the bottom index shows that you already have 2 hydrogen atoms.
    • If you multiply the coefficient of 4 by the lower index of 2, you get 8.
  • The other 6 oxygen atoms come from the bottom index 3CO2. (3x2=6 oxygen atoms + 4 other oxygen atoms =10)
  • Finish by balancing the oxygen atoms.

    Image
    Image
    • Since you've added the coefficients to the molecules on the left side of the equation, the number of oxygen atoms changes. You now have 4 oxygen atoms in a water molecule and 6 oxygen atoms in a carbon dioxide molecule. If added, the total becomes 10 oxygen atoms.
    • Add the coefficient 5 to the oxygen molecule on the left side of the equation. You now have 10 oxygen molecules on each side.

      C3H8 + 5O2 4H2O + 3CO2.

    • The carbon, hydrogen and oxygen atoms are in balance. Your equation is complete.

  • Tips

    If you're having trouble, you can type a chemical equation into an online balancer to balance it. Keep in mind that you won't have access to the online balancer while taking the exam, so don't depend on it

    Warning

    Never use fractions as coefficients in a chemical equation-because you can't make half a molecule or half an atom in a chemical reaction. To remove a fraction, multiply the entire equation (both left and right side) by the number in the denominator of your fraction

    • Balance Chemical Equations Online
    • How to Balance Chemical Equations

    Recommended: