How to balance chemical equations?

How to Balance a Chemical Equation

Balancing chemical equations is crucial in chemistry because it respects the law of conservation of mass, which states that matter cannot be created or destroyed.

Here's a step-by-step process to balance a simple chemical equation:

Step 1: Write down the unbalanced equation.

Let's consider the reaction between hydrogen ($\text{H}_2$) and oxygen ($\text{O}_2$) to produce water ($\text{H}_2\text{O}$). The unbalanced equation is:

$\text{H}_2 + \text{O}_2 \rightarrow \text{H}_2\text{O}$

Step 2: Count the number of atoms for each element in both reactants and products.

In this case, on the left side (Reactants) you have 2 hydrogen atoms and 2 oxygen atoms. On the right side (Product) you have 2 hydrogen atoms and 1 oxygen atom.

Step 3: Use coefficients (the numbers in front of atoms or molecules) to balance the equation.

We need to balance the oxygen atoms first. To do this, you can put a coefficient in front of $\text{H}_2\text{O}$ to make 2 water molecules, which gives 2 oxygen atoms:

$\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}$

Now we have 4 hydrogen atoms on the right side, so we need to balance the hydrogen atoms by putting a coefficient in front of $\text{H}_2$ on the left side:

$2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}$

Now, there are 4 hydrogen atoms and 2 oxygen atoms on both sides, so the equation is balanced.

Step 4: Check your work to make sure that there are the same number of each type of atom on both sides of the equation.

We have 4 hydrogens and 2 oxygens on both sides, so the equation is balanced.

Remember, you can only change the coefficients (the numbers in front of the molecules), not the subscripts (the numbers that tell you the number of atoms in a molecule). Changing the subscripts would change the identity of the substance.