How does one balance chemical equations?I'd missed a few days of school in a row and missed the lesson. I remember learning about it last year but I'm a bit fuzzy. My teacher had printed out the...

How does one balance chemical equations?

I'd missed a few days of school in a row and missed the lesson. I remember learning about it last year but I'm a bit fuzzy. My teacher had printed out the powerpoint of notes but that's all that was given. I need help re-grasping the concept.

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mlsiasebs | College Teacher | (Level 1) Associate Educator

Posted on

The main thing to remember for balancing equations is that we need the same number of each type of atom on each side of the arrow (i.e. reactant side vs. product side.

Let's look at a sample equation

Na + Cl2 --> NaCl

and count how many of each atom we have on each side of the equation

reactants:  Na-1, Cl-2

products:  Na-1, Cl-1

We see that we have more Cl atoms on the left so we need to add a coefficient to get the same number of Cl atoms on both sides.

Na + Cl2 --> 2NaCl

reactants:  Na-1, Cl-2

products:  Na-2, Cl-2

Now, the Cl atoms are balanced but the Na atoms are not.  Therefore we need to put a coefficient in front of the Na to get things balanced.

2Na + Cl2 --> 2NaCl

reactants:  Na-2, Cl-2

products:  Na-2, Cl-2

This was a simple exam with only a few steps but some of the equations can be more challenging to balance.  However, you can use the same approach with each problem just adding additional steps to get the atoms to balance.

The link below provides some online practice that will allow you to check your answer.

Sources:

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