Chemical equations are the source of everything in life, because they are the written version of chemical reactions. Starting with the sun, the source of all life on earth, everything is a chemical equation. Plants take sunlight, water and carbon dioxide and make oxygen and glucose through photosynthesis. The cow eats the plants, and their bodies breakdown the plant in a series of more complicated chemical reactions. The cow uses the chemicals the plant gave it to make muscles, which you and I might eat, which our bodies will break down in another series of chemical reactions. And all of life works that way. Cooking, cleaning, even sleeping is chemical. So you better know how it works, right? So, down to basics.
A chemical equation is always set up with the elements or compounds present at the beginning of the reaction of the left and the elements and compounds that come out of the reaction on the right. The little arrow indicates that a reaction is occurring here. The substances that are present at the beginning of the reaction are known, fittingly, as reactants. Substances that come out of a reaction are known as products. So in the case of the equation above, my reactants are Hydrogen and Oxygen, while my product is Water. Good so far?
Unfortunately, it is now time for me to lay down the law. Well, at least one of them. One of the biggest rules in chemistry is the Law of Conservation of Mass. The Law of Conservation of Mass states that "Matter cannot be created of destroyed; it can only be changed." In simple terms, this means that whatever amount of stuff I put in to the reaction, I have to get the same amount of stuff out, even if it's in a different form. This is where the skill of breaking down compounds comes in handy. (If you need a refresher, click here).
Lets take the example above. On my reactant side, I put in 2 Hydrogen atoms and 2 Oxygen atoms. On my product side, I have 2 Hydrogen atoms and 1 Oxygen atoms. WAIT!!! RED FLAG!!! HOLD IT!!! That isn't the same amount of stuff. That's a problem, because we have to follow the Law.
Okay, so everyone calm down. We can fix this. The only problem is the equation isn't balanced. Its up to us to balance it out, using coefficients. We can change how many sets of each reactant and product we have until it all balances out.
Unfortunately, it is now time for me to lay down the law. Well, at least one of them. One of the biggest rules in chemistry is the Law of Conservation of Mass. The Law of Conservation of Mass states that "Matter cannot be created of destroyed; it can only be changed." In simple terms, this means that whatever amount of stuff I put in to the reaction, I have to get the same amount of stuff out, even if it's in a different form. This is where the skill of breaking down compounds comes in handy. (If you need a refresher, click here).
Lets take the example above. On my reactant side, I put in 2 Hydrogen atoms and 2 Oxygen atoms. On my product side, I have 2 Hydrogen atoms and 1 Oxygen atoms. WAIT!!! RED FLAG!!! HOLD IT!!! That isn't the same amount of stuff. That's a problem, because we have to follow the Law.
Okay, so everyone calm down. We can fix this. The only problem is the equation isn't balanced. Its up to us to balance it out, using coefficients. We can change how many sets of each reactant and product we have until it all balances out.
![Picture](/uploads/2/0/1/1/20114429/4697419.png?323)
We have to get the same amount of both elements on each side. So lets play with the coefficents. Right now, I have some missing on the right side, so I'm going to say I have 2 sets of H2O.
![Picture](/uploads/2/0/1/1/20114429/1290572.png?333)
Now I have 4 Hydrogen and 2 Oxygen on the right side. That means I have the right Oxygen on both sides but now I have more Hydrogen on the right. So lets fix the left side. I need more Hydrogen, so lets say I have 2 sets of H2.
![Picture](/uploads/2/0/1/1/20114429/5533978.png?335)
Now, I have 4 Hydrogen on the left and 2 Oxygen (the blank space means just that one set). On the right, I have 4 Hydrogen and 2 Oxygen. HUZZAH! The equation is balanced.
I know that looked like a lot when its all written out like that, but chances are you won't be asked to balance many equations. If you are, just try to keep common multiples in mind. More likely, you'll be asked to simply check if an equation is balanced. Take the one below for example.
I know that looked like a lot when its all written out like that, but chances are you won't be asked to balance many equations. If you are, just try to keep common multiples in mind. More likely, you'll be asked to simply check if an equation is balanced. Take the one below for example.
![Picture](/uploads/2/0/1/1/20114429/7156733.png?250)
Is this a balanced equation? Why or why not?
These are easy questions to answer if you just break down each side like we did before.
These are easy questions to answer if you just break down each side like we did before.
![Picture](/uploads/2/0/1/1/20114429/598965.png?250)
Once it is broken down on each side, it's easy to see that this equation isn't balanced at all. There are too few Nitrogen on the product side and too many Hydrogen. Its messed up all over the place.
Let's look at one more. Try this one on your own on a piece of scratch paper. Then click the little number 2 on the side to check your answer.
Let's look at one more. Try this one on your own on a piece of scratch paper. Then click the little number 2 on the side to check your answer.