So we subtract some number x minus x gives us zero so this guy goes to zero and what we are left with is this equation where now our cell voltage will depend strictly on the concentrations of our solutions. So let's look at an example of this reaction in order to really understand what a concentration cell is, let's create one. Suppose we have the following electrochemical setup we have two has cells in hassle number one, oxidation of solid copper takes place so this electrode is solid copper and our initial concentration of aqueous copper in beaker one is zero four five molar. Now in hassle number two, reduction of copper takes place and this copper or aqueous copper becomes copper solid. Now, this electrode is also copper solid but our concentration in beaker one is 0.5 molar so this guy is more concentrated and this guy is more dilute. So let's see what the net rethink reaction for this electrochemical cell is.