During an experiment, given that other elements that make up the compound are identified, an unknown element x can easily make separate if certain properties of that unknown element is exhibited in the experiment. So, the first thing to do would be to identify the compound, identify and isolate all the knowns and one can test to see the properties which the unknown element is giving and make a reasonable deduction from that.For example if we were testing for the presence of water in Copper(II) sulfate . if water is in the sample that we were testing for, we will see that the sample will turn blue because of the presence of water
