All the layers should be kept until the experiment is complete.
<h3>What is extraction?</h3>
In chemistry, solvent extraction is accomplished by adding a sample containing the substance to be separated into a system of two solvents, an aqueous layer and an organic layer.
It is important to note that all the layers should be kept until the experiment is complete. No layer ought to be discarded before the work is completed.
Learn more about solvent extraction:brainly.com/question/11041092
Technically there is only one phase unless you account for a solution where you have a pure liquid with something dissolved in it. Unless you count aqueous as a phase which is just dissolved. Since you are in high school the answer you are looking for is one. <span />
<span>Divide the number of grams present in the sample by copper's gram atomic weight to find the number of gram atomic weights present. Then multiply that result by Avogadro's Number: 6.022137 x 10^23 atoms/gram atomic weight.1,200 g/(63.54 g/gram atomic weight) ? 18.885741 gram-atomic weights. Hope this helps. </span>
