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Symbol equations show the reactants and the products
when a chemical reaction takes place.
We always show the reactants on the left of the arrow, and
the products on the right of the arrow.
There are many things they don't say, such as how quickly a
reaction takes place, which energy changes may occur, and
whether or not a reaction even takes place.
The chemicals can be represented by their names or by
their chemical symbols.
Aluminium + Oxygen Aluminium Oxide
This is the equation for the burning of aluminium in oxygen.
If we convert each of the chemical names into the
appropriate symbols, we get the following:
Al + O2 Al2O3
You can see by looking at it that there is something wrong with
this equation. If you count the number of atoms of each type
on each side, you will see that there is only one aluminium atom
on the left side whereas there are two on the right. There are
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Here's a taster:
This clearly doesn't match.
We can balance the equation by multiplying the different
atoms and molecules on each side by different amounts.
Firstly, multiply the aluminium atoms on the left side by 4:
4Al + 3O2 2Al2O3
Now we need to put a 3 in front of the oxygen on the left
Now all we need to do to balance it is put a 2 in front of the
right side equation.…read more