balancing formulas

Balancing FormulasAn Introduction : 

Balancing FormulasAn Introduction Balancing formulas means that you end with the same number of the same elements you start with in a chemical reaction.

Balancing Formulas (continued) : 

Balancing Formulas (continued) Simple formulas are made up of: Element symbols ( N, O, Na, Cl, etc.) Subscripts showing how many of each individual element ( H2, O3 , etc.) Coefficients showing how many molecules of each compound ( 2H2O, 5NaI, etc. )

Balancing Formulas (continued) : 

Balancing Formulas (continued) You CANNOT change subscripts ( H2  H3) You CAN change coefficients (H2O  3H2O) Click on the  symbol for additional help.

Example 1 : 

Example 1 H2 + O2  H2O  __ H2 + __ O2  __ H2O  __H2 + __O2  2H2O  2H2 + __O2  2H2O We now have 4H on the left, 4H on the right and 2O on the left, 2O on the right.

Slide 5: 

It’s now balanced!

Example 2 : 

Example 2 Na + I2  NaI  __ Na + __ I2  __ NaI  __ Na + __I2  2NaI  2Na + __I2  2NaI Now Example 2 is balanced!

Step 1- Identify where you can use co-efficients : 

Step 1- Identify where you can use co-efficients You can use co-efficients before each individual element or compound, but you don’t have to! You can change co-efficients to help you balance equations. It can help to rewrite the equation putting an under line in each place where you can have a coefficient.  Back to Example 1  Back to Example 2

Step 2 – Identify which element or compound you want to increase : 

Step 2 – Identify which element or compound you want to increase Rewrite the formula placing a coefficient to make the number of one element on one side equal to the number of the same element on the other side.  Back to Example 1  Back to Example 2

Step 3 – Add or increase the coefficient for the same element on the other side : 

Step 3 – Add or increase the coefficient for the same element on the other side Rewrite the formula again placing a coefficient to make the number of that element on that side equal to the number of the same element on the other side.  Back to Example 1  Back to Example 2

Step 4 – Make sure you have an equal number of the same elements on each side : 

Step 4 – Make sure you have an equal number of the same elements on each side The formula is balanced when you have the same number of the same elements on each side. Repeat the steps as necessary Back to Example 1  Back to Example 2