In this tutorial, you will learn how to write net ionic equations. In addition, you will learn how they are useful for understanding which ions in the solution are active in a reaction and which are spectator ions.
The definition of a net ionic equation is an equation that depicts only the molecules or ions that are actively involved in the reaction or those that undergo a change. In this equation, the spectator ions are not present.
As described above, we use net ionic equations to emphasize the molecules that undergo a change in the reaction. It makes it easy to see the active molecules in a reaction, since they are the only ones present in the equation!
The first step to writing a net ionic equation is balancing the chemical equation present. Let’s use the reaction between sodium chloride and silver nitrate as an example.
Next, we write the chemical equation as a complete ionic equation. This means that we separate each molecule into its ion form. (Note that only aqueous compounds can be separated.) If the compound is a solid or liquid, it must stay in its molecule form. The complete ionic equation for the reaction above would be as follows:
Finally, we can use the complete ionic equation to write the net ionic equation. First, we identify the spectator ions. When looking at the complete ionic equation, the spectator ions will have the same charge and state of matter in the reactants and products. In this reaction, the sodium ion and the nitrate ion do not change. As a result, these are considered spectator ions. In order to write the net ionic equation, we simply need to remove the spectator ions.
After removing the spectator ions, we are left with the net ionic equation!
We can repeat this process for any reaction and obtain the net ionic equation.
Here are some examples of other chemical reactions and what their net ionic equation looks like.
Example 1:
Complete ionic equation:
Net ionic equation:
Example 2:
Complete ionic equation:
Net ionic equation:
Example 3:
Complete ionic equation:
Net ionic equation:
To understand a net ionic equation even better, you can perform this fun, safe and simple home chemistry experiment. And you probably have everything you need! Watch the video, and please subscribe to our YouTube channel – lots more amazing videos are on the way!
The net equation for the reaction in the video is Mg +2 + CO3 -2 -> MgCO3(s)
