How to balance chemical equations in five easy steps.
Step one: Count the atoms on each side of the equation.
Let's count each type of atom. Sulfur I have eight.
Oxygen, I have two. On the product side, Sulfur I have one and oxygen I have two.
Note that if there's nothing after an element we assume that to be "1".
And that's it we're done with the first step. Smooth.
The big rule for balancing equations is that we can only change the coefficients.
Those are the numbers in front of the atoms.
The numbers after the atoms, the subscripts, CANNOT be changed
So let's balance this equation by changing the coefficients.
If there's no coefficient written we assume that it's "1". So right now there's a one in front of
each of these terms. We can see that we have two oxygens on each side of the
equation. So the oxygens are fine, but the sulfur atoms we have eight on the left
side, the reactants ,and only one on the right. To fix that I can change
the coefficient in front of the Sulfur on the right and make that eight.
So if I put in a here that means, eight times the one sulfur, that'll give me eight Sulfurs.
And now my Sulfurs on both sides are eight, but this eight here is also times the two oxygens
and that gives me sixteen oxygens. So I fixed the Sulfurs but the oxygens
aren't balanced. I can change the coefficient here though to eight,
eight times 2 equals 16. Now I have eights Sulfurs on each side and
I have 16 oxygens on each side of the equation. This equation is balanced.
Step 3, so you don't forget only change the coefficients! Let's try another problem.
So in this equation we have two hydrogens, two oxygens, over here two
hydrogens and one oxygen. How bout, let's see ... I'll put 2 right here. So 2 x 2,
that gives me 4 hydrogens.
But 2 times the 1, that'll give me 2 oxygens. So my oxygens are so my oxygens are balanced now
but my hydrogens are messed up. What I can do over here is put it 2 in front
of hydrogen and now 2 x 2, that will give me 4. And now the atoms on each side of
the equation of the same. This equation is balanced. Sometimes will have equations
that look downright scary. Yikes. But if we have a polyatomic ion on both sides,
like the SO4 or the NO3, then we can consider that to be just one thing. Let's see how
that works. So here's the equation and I have done my accounting below. You can
see I have 1 calcium here, 1 calcium over here, and then I wrote the entire
SO4 as one thing. And I have 1 of those here and over here I have one SO4.
Na's, 1, 2 Na's on this side, and over here 1 NO3. And I have 1 NO3, but
that 2 on the outside I have 2 of them. So I have 2 NO3s.
So if I put the coefficient of 2 right here that means all have 1 x 2 = 2 Na's.
But this 2 also multiplies across. So 1 x 2 for the NO3s that gives me 2.
And now everything is balanced. So by treating those polyatomic ions is just
one thing that makes it a pretty simple equation to balance. Let's wrap up with
one that sometimes gives people problems. So we can see we have 1 carbon,
4 hydrogens and 2 oxygens. Easy. Over here we have 1 carbon and then we have
2 oxygens, and then we have two hydrogens. But be careful. We have to count this
oxygen over here as well. So we have 1 + 1 that'll give us 3 total
oxygens. I'll start by balancing the hydrogens. If I put it 2 in front of
this hydrogen, 2 x 2, that will give me four. And that'll fix the hydrogens.
But now I have 2 oxygens.
plus 2 x 1 oxygens. that gives me a total of four oxygents. But that's
good because now I put a 2 right here and change this coefficient, 2 x 2 = 4
And now everything is balanced. This video has given you the basics for
balancing equations but you've gotta practice to gain speed and expertise.
The more you practice the easier it becomes. This is Dr.B and thanks for watching.