I dont understand balancing chemical equations?

Think about it as a math problem... the total number of atoms on each side has to be equal... subscripts are the small numbers after the element symbol and coefficients are the large numbers before... you can only change coefficients to take them equal...

Say your equation was 4H +2O -> H2O (that 2 should be a subscript)

You have 4 Hydrogen on the left of the arrow and 2 on the right. To make it equal you need to multiply by 2. So, add a 2 coefficient in front of the molecule on the right.

You have 2 Oxygen on the left and now since you added a coefficient of 2 on the right it also distributes to the oxygen so you have 2 on the right; therefore, since all of the numbers of atoms on each side are equal its balanced.

I am a science teacher, and this year I taught my 8th graders how to do this by using a free computer app called chembalancer... I don't have the direct link here,but id suggest google searching it; its amazing.. it will draw out all of the atoms for you so that you can add coefficients and count the atoms until they match... its great practice and is great for visual learning of it..

balancing equations involves manipulating chemical equations in order to have the same amount of reactants as products
For example the equation for photosynthesis is

CO?+H?O -------> C?H??O? + O?

Start from the left hand side of the equation:
How many carbons are on the left side?
there is 1
Now check how many are on the right side of the equation?
There are six, so you place a 6 in front of the carbon on the left side of the equation so theres an
equal amount of it on both sides.

Next: How many Hydrogens are on the left?
There are only 2

How many are on the right side of the equation?
There are 12; SO we need to put a 6 in front of the H?O molecule on the left hand side in order to make the amount of hydrogen equal-- 2hydrogens x 6 =12hydrogen

Lastly the oxygen:

So far our equation looks like this;;
6CO?+6H?O -------> C?H??O? + O?

How many oxygen on the left? We now have 6CO?'s so theres 12 oxygen's in there and in the 6H?O we have 6 oxygens altogether thats 18 oxygen.

How many do we have on the right? we have 6 in C?H??O? and 2 in the O? altogether that's 8.
How do we make that into 18?--- We need to put a number in front of the O? (if you put it in front of the  C?H??O? then you'll have to re-balance everything as the number in front of the molecule effects the whole molecule not just one element in it)

We have 6 oxygens in C?H??O? how many do we need to add to that in order to make 18? 18-6=12
How do we make the O? into 12 oxygens? we put a 6 in front (6x2=12)

Overall equation is 6CO?+6H?O -------> C?H??O? + 6O?


I really hope that helped... if you need more help just let me know i'd be glad to explain further ^~^