OK. You know why you need to balance chemical equations, but you don't yet know how to do it. It turns out that I'm star who knows how to explain things in a way that even the dumbest people know how to follow. And, hey, if the dumbest people can figure it out, so can you!
Listen: There are four e...
... Balancing Chemical Equations
OK. You know why you need to balance chemical equations, but you don't yet know how to do it. It
turns out that I'm star who knows how to explain things in a way that even the dumbest people know
how to follow. And, hey, if the dumbest people can figure it out, so can you!
Listen: There are four easy steps that you need to follow to make this work. Here they are:
1. Get yourself an unbalanced equation. I might give this to you, or I might make you figure it out.
Either way, if you don't have an equation with all the chemical formulas and the arrow and all that
other stuff, then you're out of luck.
2. Draw boxes around all the chemical formulas. Never, ever, change anything inside the boxes.
Ever!!! Really!!! If you do, you're guaranteed to get the answer wrong.
3. Make an element inventory. How are you going to know if the equation is balanced if you don't
actually make a list of how many of each atom you have? You won't. You have to make an inventory of
how many atoms of each element you have, and then you have to keep it current throughout the
whole problem.
4. Write numbers in front of each of the boxes until the inventory for each element is the same both
before and after the reaction. Whenever you change a number, make sure to update the inventory -
otherwise, you run the risk of balancing it incorrectly. When all the numbers in the inventory balance,
then the equation can balance.
An example of equation balancing:
Let's say I ask you the following thing on a test: "Balance the equation that takes place when sodium
hydroxide reacts with sulfuric acid to form sodium sulfate and water." How do we solve this using the
steps above?
1. Get yourself an unbalanced equation. Here's where you use your knowledge of formulas to help
you out. If you know what the formula of sodium hydroxide, sulfuric acid, sodium sulfate, and water
are, you'd be able to write the following unbalanced equation:
2. Draw boxes around all the chemical formulas. This is the step that people frequently don't do
because they feel that it's a stupid thing to do. Those people are morons. Ignore them. You're drawing
those boxes so that you'll be sure not to mess around with the formulas to balance the equation. While
they all suffer in the pits of academic hell, you'll be laughing from the honor roll. Here's what the
equation looks like:
, 3. Make an element inventory. In this inventory, your job is to figure out how many atoms of each
element you have on the left and right sides of the equation. Now, if you look at the equation, you
should be able to see that on the left side of the equation there is one sodium atom, five oxygen atoms
(one from the sodium hydroxide, four from the sulfuric acid), three hydrogen atoms (one from the
sodium hydroxide, two from the sulfuric acid), and one sulfur atom. On the right side of the equation,
there are two atoms of sodium, one atom of sulfur, five atoms of oxygen (four from the sodium sulfate
and one from the water), and two atoms of hydrogen. Thus, your element inventory should look like
this:
4. Write numbers in front of each of the boxes until the inventory for each element is the same both
before and after the reaction. Now, what happens when we put a number in front of a formula?
Basically, anything in that box is multiplied by that number, because we're saying that we have that
many of that kind of molecule. So, looking at the inventory, what should we do?
Well, we can see that on the left side of the inventory, there is one atom of sodium and on the right
there are two. The solution: Stick a "2" in front of the sodium hydroxide on the left side of the equation
so that the numbers of sodium atoms are the same on both sides of the equation. When we do this,
the new atom inventory should look like this: (I'll let you figure out how this is done)
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