Chemical Reactions and Balancing Chemical Equations
Instructor: Amy Meyers
Amy holds a Master of Science. She has taught science at the high school and college levels.
Conservation of Matter
Remember that equations can be written in word form, such as methane + oxygen = carbon dioxide + water. but more often they are written in a shorthand fashion called a formula equation. This looks like CH4 + O2 = CO2 + H2O. There is something wrong with this equation, though. This equation is not a balanced equation. To be correctly written it must have the same amount of elements on both sides of the equation, and if you look, it doesn't. It has four hydrogens on the left, but only two hydrogens on the right. That means matter was destroyed somewhere, and we know that can't happen.
How to Balance an Equation
To write a balanced equation, here are the steps.
Step 1: If you are given a word equation such as water = hydrogen + oxygen.
turn it into a formula equation. H2O = H2 + O2.
Step 2: Balance the different types of atoms one at a time.
Step 2a: First balance the atoms that are combined and appear only once on each side of the equation.
Step 2b: Balance other compounds that appear on both sides of the equation.
Step 2c: Balance the hydrogen (H) atoms and oxygen (O) atoms last.
Step 3: Count the atoms on each side of the equation to make sure it is balanced.
So here is the way it would work. You are given water = hydrogen + oxygen.
Step 1: You rewrite it as H2O = H2 + O2.
Step 2 a: Balance the atoms that are combined and only appear once. Hmmm. This doesn't apply too much in this example.
Step one is changing the word equation into its equivalent coumpounds.
Step 2b: There are no compounds on either side, so skip this step.Source: study.com