How do you balance chemical equations?

[Heil_Kaiba8921]

I sort of remember doing this last semester, i didn't get it at first but my science teacher was on her first year at my skool so she actually CARED and helped me out when i asked for help (i really didn't wanna swallow my pride and ask though because i can usually make up for that in the next chapter) and basically, it's like when you're solving for X in math problems...

4H+9OH->12H+2OH

...

actually, after typing it out i realized i didn't really remember it, but i know that the arrow stands for "yields" and what you're technically trying to do is get the arrow to actually be 2 arrows (in a picture anyways) that point to both sides of the equation because that means that they are tranferring at an equal rate.

I'm going to send my old teacher an email and if she replies quickly i'll post what she says.

P.S. My teacher is like, really sick right now and the doctors didn't really know what it was but it was best for her not to go back to skool because of all the germs there...so she has been gone all year (doubt she'll make it back in the next couple of weeks though)

EDIT: the equation i wrote was pretty bad for a sample equation...here is one that she put on a practice worksheet of hers.(don't worry about the square, it's just the arrow pointing to the right in word)

1. _____NaBr +______Ca(OH)2 _____NaOH + ____CaBr2

here are some steps for you to solve this:

1: multiply the NaOH by 2 so that it makes
_____NaBr +______Ca(OH)2 __2_NaOH + ____CaBr2

2: since you have "2 Na's" you need to multiply the NaBr by 2 so that it looks like this
_2__NaBr +______Ca(OH)2 __2_NaOH + ____CaBr2

after that you're done, this was a double replacement which just means that you have to mess with stuff on both sides (the science terms are different, but mean the same things) and in single replacements you just mess with one side usually(unless you want ot multiply by like 28 or something for no reason other than you can)

Single Replacement example:

2. _____Zn +______ AgNO3_______ ZnNO3 + _____Ag

1: multiply the Zn by 3 to make
_3___Zn +______ AgNO3_______ ZnNO3 + _____Ag

and it's balanced because there are 3 Zn's, 1 Ag's and 3 ZnNO3's
(i'm pretty sure that this is single replacement, it could be one where you do nothing because it's already balanced...but pretend that it's not balanced for the sake of laziness)
___________________________________________________________________

What she would do to help us remember this stuff was to first write out how many of each element you had on each side so in the second equation it would be

left side: 1 Zn
1 Ag
3 NO

Right side: 1 Zn
3 NO
1 Ag

and from that you could figure what to multiply by to make them equal (writing down what you end up with next to them is helpful for keeping track too and let me know if you want to see the worksheet i downloaded for additional references for problems because these were the first two that were on there)