Why do you have to balance chemical equations?

Question

and how do you balance this one?

Sn + KOH ----> K(2)SnO(2) + H(2)

This (2) means that the two is on the bottom of th element

thanks?!

Answer 1

the law of conservation of mass says that mass cannot be created nor destroyed in a chemical reaction - this means that the number and kind of atoms MUST be the same on both sides of the arrow (otherwise the mass would change)

Sn + 2 KOH ----> K(2)SnO(2) + H(2)

Answer 2

chemical reactions involve making and breaking chemical bonds. the identities of the atoms are unchanged. so although the atoms may appear in different molecules, you must have the same number of atoms of each type on both sides of the reaction.

first step is to count the number of atoms of each type in the unbalanced equation. there is one Sn on either side, and one K, O and H on the left and two K, O and H on the right. you can balance equations by placing multipliers in front of molecules, the simplest way to balance this one is by doubling the number of KOH molecules on the left:

Sn + 2KOH -> K(2)SnO(2) + H(2)