balancing chemical equations, help plz<3 Options

[KERP1UNK]

balancing chemical equations.
how do i do this?
i seriously don't get it..........
and my science final is 100 of these questions!!
help would be greatly appreciated!!

[Gigi]

Okay, so you have to understand that in a chemical equation, the number of atoms in your reactants and the number of atoms in your products MUST be exactly the same; it's a law.

So I take it you understand the notation? The subscript 2 after the H and O means that there are 2 hydrogen atoms and 2 oxygen atoms. The blanks in front are for you to put regular script numbers, and those regular script numbers tell you how many molecules of each group of atoms there are.

So say I put 2 in front of H-subscript2, that just means there are 2 groups of 2 hydrogen atoms, which means there are 4 atoms of hydrogen. Got me so far?

So to balance that equation, the easiest, least complicated way to do it is to put the atoms in lists.

__H-subscript2 + __O-subscript2 --> __H-subscript2-O

On the reactants side, you have:
2 hydrogen atoms
2 oxygen atoms

On the products side, you have:
2 hydrogen atoms
1 oxygen atom

In order to balance out the oxygen molecules, try adding a regular script 2 in front of the water molecule. That'll multiply all your atoms in the molecule by two.

2H-subscript2-O:
4 hydrogen atoms
2 oxygen atoms.

Now that your oxygen atoms are equal in both the reactants and products, we have to deal with the imbalance of the hydrogen atoms. And this is simple.

You have 4 hydrogen atoms in the product, and 2 hydrogen atoms in the reactants...so that means you have to times the h-subscript2 by 2 to get 4 hydrogen atoms in the reactants.

2H-subscript2 + O-subscript2 --> 2H-subscript2-O

And there you are. A balanced equation.

That probably made NO SENSE.