Whats the method with balancing equations in chemistry?

[LittleStar=]]

Step By Step Method Would Be Great.. You Can Use An Example If It Makes The Explaination Easier..
Thank You

[smirnoff_princess_006]

make sure there is the same number of moles of the element in both sides of the equation

for eg:

H + OH --------> H2O

This is already balanced
there are 2 moles of H and 1 mol of O on both sides of the eq

[Tukie]

each element obveously has to ballance on eather side.

Start adding coefficents to the compounds, but when you have an odd number of a product element, double all of the compounds on either side.

[Farzin]

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, and you can relax and enjoy a delicious bowl of Mr. Guch's chili.

Source: http://misterguch.brinkster.net/eqnbalance.html

[Luton]

Tin oxide is heated with hydrogen gas to form tin metal and water vapor. Write the balanced equation that describes this reaction.

1. Write the unbalanced equation.

SnO2 + H2 --> Sn + H2O

Refer to Table of Common Polyatomic Ions and Formulas of Ionic Compounds if you have trouble writing the chemical formulas of the products and reactants.

2. Balance the equation.

Look at the equation and see which elements are not balanced. In this case, there are two oxygen atoms on the lefthand side of the equation and only one on the righthand side. Correct this by putting a coefficient of 2 in front of water:

SnO2 + H2 --> Sn + 2 H2O

This puts the hydrogen atoms out of balance. Now there are two hydrogen atoms on the left and four hydrogen atoms on the right. To get four hydrogen atoms on the right, add a coefficient of 2 for the hydrogen gas. Remember, coefficients are multipliers, so if we write 2 H2O it denotes 2x2=4 hydrogen atoms and 2x1=2 oxygen atoms.

SnO2 + 2 H2 --> Sn + 2 H2O

The equation is now balanced. Be sure to double-check your math! Each side of the equation has 1 atom of Sn, 2 atoms of O, and 4 atoms of H.

3. Indicate the physical states of the reactants and products.

To do this, you need to be familiar with the properties of various compounds or you need to be told what the phases are for the chemicals in the reaction. Oxides are solids, hydrogen forms a diatomic gas, tin is a solid, and the term 'water vapor' indicates that water is in the gas phase:

SnO2(s) + 2 H2(g) --> Sn(s) + 2 H2O(g)

This is the balanced equation for the reaction.