IBDP/MYP How to Balance Chemical Equations
- ES
- Nov 14, 2020
- 2 min read
When you learn chemistry, balancing chemical equations are the most basic skill that you need. If you can't even balance chemical equations, you can't solve questions on IB tests. However, when you first meet this challenge, you don't know where to start and make lots of mistakes. So in this post, I will teach you how to do it.
What are the chemical equations?
A chemical equation is the symbolic representation of a chemical reaction. You can know what are reactants and products by looking at the equation. Also, you can predict how much reactants you need to make a certain amount of products only by looking at the equation.
In chemical equations, there are formulas and the subscript and the coefficient. The subscript means in one glucose, there are 6 carbon atoms, 12 hydrogens atoms, 6 oxygen atoms. The coefficient means there are 6 oxygen molecules. This equation means if one glucose and 6 oxygen molecule react, 6 carbon dioxide and 6 water molecules are formed.
Why do we need to balance chemical equations?
Chemical equations need to be balanced because of the law of conservation of mass. This means that neither of matter is created nor destroyed. Hence, the number of atoms of reactants and products are the same.
How to balance chemical equations?
Now let's learn how to balance chemical equations.
step 1: write formulas for the equation.
step 2: count down the number of atoms at the reactant side and the product side. remember that the number of atoms should be same at both sides.
step 3: look at subscripts. Focus on huge subscripts and start with the single atom. try to find least common multiple of the subscript of the reactant and the product and remember that you can only write the coefficient. You need to time the coefficient to the subscript and that will be the total number of the atoms. (save single atom molecules for later and focus on molecules with different types of atoms)
step 4: then look at the other atom that was in the same formula at 3 step if you write 3 for the coefficient, multiple the coefficient to the subscript of the atom. Now you need that much of atoms at opposite side. Find least common multiple of number of atoms again.
step 5: repeat step 4 until the equation is balanced.
How to be good at balancing chemical equations
There is no other way. You need to practice and you will get used to it.
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