It is necessary to make a logical system for naming compounds because there are so many of them and thinking of arbitrary random names for each one and then later remembering them all would be impossible. Also, they need to be all recognized and standardized for global use so as to have everyone use the same system.
Use Avogadro's number to calculate the number of moles of Mg<span>Cl2 . The number of moles of Cl is twice as </span>much, because the ratio of Cl in MgCl2 to MgCl2 is 2:1. 3.61⋅10246.022⋅10<span>23=5.99. Therefore, there are 12 moles of Cl.</span>
Find the proportion, and multiply it by 100 to get the percentage.
The proportion is 2.9/3.1=0.935
The percentage is 0.935*100=93.5
0.702 mol / dm³.
<h3>Explanation</h3>
Consider a 1,000 mL sample of this solution. Mass of the sample:
.
The mass ratio of copper(II) sulfate pentahydrate in this sample is 15 %. In other words, 
among that 1,167 grams of the solution is 
.
Number of moles of in that 
of the hydrate:
.
Concentration of the hydrate:
.
